The United States of America
is located in the middle of the North American continent, with Canada
to the north and the United Mexican States
to the south. The United States ranges from the Atlantic Ocean
on the nations east coast to the Pacific Ocean
bordering the west, and also includes the state of Hawaii
, a series of Islands located in the Pacific Ocean, the state of Alaska
located in the northwestern part of the continent above the Yukon
, and numerous other holdings and territories.
The first known inhabitants of the area now possessed by the United States are believed to have arrived over a period of several thousand years beginning approximately 20,000 years ago by crossing the Bering land bridge into Alaska. The first solid evidence of these cultures settling in what would become the US begins as early as 15,000 years ago with the Sandia and Clovis tribes.
Relatively little is known of these early settlers compared to the Europeans who colonized the area after the first voyage of Italian navigator Christopher Columbus in 1492. Columbus' men were also the first known Old Worlders to land in the territory of the United States when they arrived in Puerto Rico during their second voyage. The first European known to set foot in the continental U.S. was Juan Ponce de León, who arrived in Florida in 1513, though there is some evidence suggesting that he may have been preceded by John Cabot in 1497.
 Pre-Colonial America
in Cahokia, Illinois
, at 100 feet high is the largest man-made earthen mound in North America, was part of a city which had thousands of people around 1050 AD
Archaeological as well as Geological evidence suggests that the present-day United States was originally populated by people migrating from Asia via the Bering land bridge starting some 20,000 years ago. These people became the indigenous people who inhabited the Americas prior to the arrival of European explorers in the 1400s and who are now called Native Americans.
Many cultures thrived in the Americas before Europeans came, including the Puebloans (Anasazi) in the southwest and the Adena Culture in the east. Several such societies and communities, over time, intensified this practice of established settlements, and grew to support sizeable and concentrated populations. Agriculture was independently developed in what is now the eastern United States as early as 2500 BC, based on the domestication of indigenous sunflower, squash and goosefoot. Eventually, Mexican maize and legumes were adapted to the shorter summers of eastern North America and replaced the indigenous crops.
The first European contact with the Americas was with the Vikings in the year 1000. Leif Erikson established a short-lived settlement called Vinland in present day Newfoundland. It would be another 500 years before European contact would be made again.
 Early European exploration and settlements
After a period of exploration by various European countries, Dutch, Spanish, English, French, Swedish, and Portuguese settlements were established. Columbus was the first European to set foot on what would one day become U.S. territory when he came to Puerto Rico in 1493. In the 15th century, Europeans brought horses, cattle and hogs to the Americas.
 Spanish exploration and settlement
- See also: New Spain
Spaniards explorers reached the present-day United States. The first confirmed landing in the continental US was by a Spaniard, Juan Ponce de León, who landed in 1513 at a lush shore he christened La Florida.
An anachronous map showing areas of the United States and other territories pertaining to the Spanish Empire over a period exceeding 400 years.
Within three decades of Ponce de León's landing, the Spanish became the first Europeans to reach the Appalachian Mountains, the Mississippi River, the Grand Canyon and the Great Plains. In 1540, De Soto undertook an extensive exploration of the present US and, in the same year, Francisco Vázquez de Coronado led 2,000 Spaniards and Mexican Indians across today's Arizona-Mexico border and traveled as far as central Kansas. Other Spanish explorers include Lucas Vásquez de Ayllón, Pánfilo de Narváez, Sebastián Vizcaíno, Juan Rodríguez Cabrillo, Gaspar de Portolà, Pedro Menéndez de Avilés, Álvar Núñez Cabeza de Vaca, Tristán de Luna y Arellano and Juan de Oñate.
The Spanish sent some settlers, creating the first permanent European settlement in the continental United States at St. Augustine, Florida, in 1565 and later Santa Fe, New Mexico, San Antonio, Tucson, San Diego, Los Angeles and San Francisco. Most Spanish settlements were along the California coast or the Sante Fe River in New Mexico.
 French colonization (1655-1803)
- See also: New France
 English/British Colonial America (1493-1776)
The strip of land along the seacoast was settled primarily by English colonists in the 17th century, along with much smaller numbers of Dutch and Swedes. Colonial America was defined by a severe labor shortage that gave birth to forms of unfree labor such as slavery and indentured servitude, and by a British policy of benign neglect (salutary neglect) that permitted the development of an American spirit distinct from that of its European founders.
The first successful English colony was established in 1607, on the James River at Jamestown. It languished for decades until a new wave of settlers arrived in the late 17th century and set up commercial agriculture based on tobacco. One example of conflict between Native Americans and English settlers was the 1622 Powhatan uprising in Virginia, in which Indians had killed hundreds of English settlers. The largest conflict between Native Americans and English settlers in the 17th century was King Philip's War in New England. 
New England was founded primarily by Puritans who established the Massachusetts Bay Colony in 1629. The Middle Colonies, consisting of the present-day states of New York, New Jersey, Pennsylvania, and Delaware, were characterized by a large degree of diversity. The first attempted English settlement south of Virginia was the Province of Carolina, with Georgia Colony the last of the Thirteen Colonies established in 1733. Several colonies were used as penal settlements from the 1620s until the American Revolution.
 Formation of the United States of America (1776-1789)
The United States declared its independence in 1776 and defeated Great Britain with help from France in the American Revolutionary War. As Seymour Martin Lipset points out, "The United States was the first major colony successfully to revolt against colonial rule. In this sense, it was the first 'new nation.'" (Lipset, The First New Nation (1979) p. 2)
On July 4, 1776, the Second Continental Congress, still meeting in Philadelphia, declared the independence of a nation called "the United States of America" in the Declaration of Independence, primarily authored by Thomas Jefferson. July 4 is celebrated as the nation's birthday. The new nation was dedicated to principles of republicanism, which emphasized civic duty and a fear of corruption and hereditary aristocracy.
The structure of the national government was profoundly changed on March 4, 1789, when the people replaced the Articles of Confederation with the United States Constitution. The new government reflected a radical break from the normative governmental structures of the time, favoring representative, elective government with a weak executive, rather than the existing monarchial structures common within the western traditions of the time. The system of republicanism borrowed heavily from Enlightenment Age ideas and classical western philosophy in that a primacy was placed upon individual liberty and upon constraining the power of government through division of powers and a system of checks and balances.
The colonists' victory at Saratoga led the French into an open alliance with the United States. In 1781, a combined American and French Army, acting with the support of a French fleet, captured a large British army, led by General Charles Cornwallis, at Yorktown, Virginia. The surrender of General Cornwallis ended serious British efforts to find a military solution to their American problem.
A series of attempts to organize a movement to outline and press reforms culminated in the Congress calling the Constitutional Convention of 1787, which met in Philadelphia, Pennsylvania.
 Westward expansion (1789–1849)
Economic growth in America per capita income
Territorial expansion of the United States, omitting Oregon and other claims.
George Washington—a renowned hero of the American Revolutionary War, commander and chief of the Continental Army, and president of the Constitutional Convention—became the first President of the United States under the new U.S. Constitution. The Whiskey Rebellion in 1794, when settlers in the Monongahela River valley of western Pennsylvania protested against a federal tax on liquor and distilled drinks, was the first serious test of the federal government.
The Louisiana Purchase, in 1803, gave Western farmers use of the important Mississippi River waterway, removed the French presence from the western border of the United States, and provided U.S. settlers with vast potential for expansion. In response to continued British impressment of American sailors into the British Navy, Madison had the Twelfth United States Congress— led by Southern and Western Jeffersonians — declare war on Britain in 1812. The United States and Britain came to a draw in the War of 1812 after bitter fighting that lasted until January 8, 1815. The Treaty of Ghent, officially ending the war, essentially resulted in the maintenance of the 'status quo ante bellum'; crucially for the U.S., the British ended their alliance with the Native Americans.
The Monroe Doctrine, expressed in 1823, proclaimed the United States' opinion that European powers should no longer colonize or interfere in the Americas. This was a defining moment in the foreign policy of the United States.
In 1830, Congress passed the Indian Removal Act, which authorized the president to negotiate treaties that exchanged Indian tribal lands in the eastern states for lands west of the Mississippi River. This established Andrew Jackson, a military hero and President, as a cunning tyrant in regards to native populations. The act resulted most notably in the forced migration of several native tribes to the West, with several thousand Indians dying en route, and the Creeks' violent opposition and eventual defeat. The Indian Removal Act also directly caused the ceding of Spanish Florida and subsequently led to the many Seminole Wars.
Mexico refused to accept the annexation of Texas in 1845, and war broke out in 1846. The U.S., using regulars and large numbers of volunteers, defeated Mexico which was badly led, short on resources, and plagued by a divided command. Public sentiment in the U.S. was divided as Whigs and anti-slavery forces opposed the war. The 1848 Treaty of Guadalupe Hidalgo ceded California, New Mexico, and adjacent areas to the United States. In 1850, the issue of slavery in the new territories was settled by the Compromise of 1850 brokered by Whig Henry Clay and Democrat Stephen Douglas.
 Civil War era (1849–1865)
In the middle of the 19th century, white Americans of the North and South were unable to reconcile fundamental differences in their approach to government, economics, society and African American slavery. Abraham Lincoln was elected President, the South seceded to form the Confederate States of America, and the Civil War followed, with the ultimate defeat of the South.
In 1854, the proposed Kansas-Nebraska Act abrogated the Missouri Compromise by providing that each new state of the Union would decide its stance on slavery. After the election of Lincoln, eleven Southern states seceded from the union between late 1860 and 1861, establishing a rebel government, the Confederate States of America on February 9, 1861.
The Union: blue, yellow, red; The Confederacy: brown
The Civil War began when Confederate General Pierre Beauregard opened fire upon Fort Sumter. They fired because Fort Sumter was in a confederate state. Along with the northwestern portion of Virginia, four of the five northernmost "slave states" did not secede and became known as the Border States. Emboldened by Second Bull Run, the Confederacy made its first invasion of the North when General Robert E. Lee led 55,000 men of the Army of Northern Virginia across the Potomac River into Maryland. The Battle of Antietam near Sharpsburg, Maryland, on September 17, 1862, was the bloodiest single day in American history.
At the beginning of 1864, Lincoln made General Ulysses S. Grant commander of all Union armies. General William Tecumseh Sherman marched from Chattanooga, Tennessee, to Atlanta, Georgia, defeating Confederate Generals Joseph E. Johnston and John Bell Hood. Sherman's army laid waste to about 20% of the farms in Georgia in his "March to the Sea", and reached the Atlantic Ocean at Savannah in December 1864. Lee surrendered his Army of Northern Virginia on April 9, 1865, at Appomattox Court House.
Reconstruction and the rise of industrialization (1865–1918)
After the Civil War, America experienced an accelerated rate of industrialization, mainly in the northern states. However, Reconstruction and its failure left the Southern whites in a position of firm control over its black population, denying them their Civil Rights and keeping them in a state of economic, social and political servitude.
U.S. Federal government policy, since the James Monroe Administration, had been to move the indigenous population beyond the reach of the white frontier into a series of Indian reservations. Tribes were generally forced onto small reservations as white farmers and ranchers took over their lands. In 1876, the last major Sioux war erupted when the Black Hills Gold Rush penetrated their territory.
in 1902, the main immigration port for immigrants entering the United States in the late 19th and early 20th centuries.
An unprecedented wave of immigration to the United States served both to provide the labor for American industry and to create diverse communities in previously undeveloped areas. Abusive industrial practices led to the often violent rise of the labor movement in the United States.
The United States began its rise to international power in this period with substantial population and industrial growth domestically and numerous military ventures abroad, including the Spanish-American War, which began when the United States blamed the sinking of the USS Maine (ACR-1) on Spain without any real evidence.
This period was capped by the 1917 entry of the United States into World War I.
 Post-World War I and the Great Depression (1918–1940)
US territorial growth, 1810-1920
Following World War I, the U.S. grew steadily in stature as an economic and military world power. The after-shock of Russia's October Revolution resulted in real fears of communism in the United States, leading to a three year Red Scare.
agents destroying barrels of alcohol in Chicago, 1921
The United States Senate did not ratify the Treaty of Versailles imposed by its Allies on the defeated Central Powers; instead, the United States chose to pursue unilateralism, if not isolationism.
In 1920, the manufacture, sale, import and export of alcohol was prohibited by the Eighteenth Amendment to the United States Constitution. The 'Prohibition' fueled illegal breweries and dealers to make substantial amounts of money selling alcohol illegally. The Prohibition ended in 1933, a failure.
During most of the 1920s, the United States enjoyed a period of unbalanced prosperity: farm prices and wages fell, while industrial profits grew. The boom was fueled by a rise in debt and an inflated Stock Market. The 1929 Stock Market crash, Dust Bowl, and the ensuing Great Depression led to government efforts to re-start the economy and help its victims, with Franklin D. Roosevelt's New Deal. The recovery was rapid in all areas except unemployment, which remained fairly high until 1940.
 World War II (1940-1945)
After the outbreak of World War II, as was the case with World War I, the United States was the last of the active Allied countries to declare war when it was forced to become the 17th country to declare war following the attack on Pearl Harbor. Until now the Isolationalism policy had bound the country by law to neutrality until a hostile attack was made on American soil. Any potential active contributions that the United States could have made upon the outbreak of war on the 3rd of September 1939 were limited by the general unpreparedness of the country for a conflict of such a magnitude. The American armed forces were significantly smaller than the equivalent forces of France, Germany, Britain, The Soviet Union and Japan, allowing president Franklin Roosevelt to justify this neutrality to allow the country time to rearm.
The United States first contribution to the war was to cut off oil and raw material supplies desperately needed by Japan for it to maintain its offensive in Manchuria, while at the same time increasing military and financial aid to China. The first contribution to the allied powers came approximately 1 year after the outbreak of war in September 1940 when the United States gave Britain 50 old destroyers in exchange for military bases in the Caribbean. This was followed in December 1940 when the United States began a "Lend Lease" program with Britain, supplying much needed Military equipment.
On 31 October 1941, less than two months before the attack on Pearl Harbor, an American destroyer which was escorting cargo ships in the Atlantic was sunk by a German U-Boat. War however was not declared on Germany. Finally on 7 December 1941 Japan attacked the American naval base in Pearl Harbour, citing Americas trade embargo with them as justification for the attack. Franklin D Roosevelt saw it as "A date which will live in Infamy", the rest of the world saw it as the waking of a sleeping giant. The now well prepared armed forces of the United States entered the fold immediately.
Battle against Germany
Upon entering the war the United States realized they could not fight both Japan and Germany at once. Thus it was decided to concentrate the bulk of their efforts on fighting Hitler in Europe, whilst maintaining a defensive position in the Pacific until Hitler was defeated. The United States first step was to set up a large airforce in Britain to concentrate on bombing raids into Germany itself. America brought a bomber to the war that was vastly superior to anything that had flown before, the B-17 Flying Fortress. Britain had long given up on daylight bombing raids, due to heavy casualties inflicted by German ground defences and the Luftwaffe. However the technical superiority of the B-17 allowed the Americans to conduct precision bombing raids through the day, whilst the British continued the attack throughout the night. Germany was bombed 24 hours a day from August 1942 to the end of the war in Europe.
The American army's first ground action was fighting alongside the British and Australian armies in North Africa, to reclaim the Suez canal and important ground in North Africa that had been won by Rommel in the previous 12 months of fighting. This ground was one of the two crucial cargo links that Britain relied on throughout the war, along with the Atlantic. By May 43 the Germans had been expelled from North Africa and the Allies controlled this vital link until the end of the war. The American navy also played a crucial defensive role in the Atlantic protecting the cargo lines bringing American war equipment and supplies to Britain itself. By midway through 1943 the Allies were fighting the war from Britain with unbroken supply lines, whilst at the same time Hitler's armies were very much on the back foot, with heavy bombing taking its toll on production. The tide had swung dramatically from the grim days of early 1942.
By early 1944 a planned invasion of Western Europe was underway. Germany fully expected this attack to occur, but brilliant allied strategy and a complete lack of intelligence flowing to Germany from Britain following the efficient elimination of virtually all German spies by the British SS allowed this attack to occur largely as a surprise. What followed on the 6th of June 1944 was Operation Overlord, or D-Day. The largest war armada ever assembled landed on the beaches of Normandy and began the penetration of Western Europe that eventually overthrew Hitler and Nazi Germany. Hitler had fallen for the Allied bluff and prepared most of his troops for an invasion at Calais, much further north than where the actual landing would take place. It wasn't until the attack was well underway that the German army realised what was occurring and sent forces in defense. It was too late. In all, almost 5,000 ships, 10,000 aircraft and 176,000 troops took part in the 6 week battle that ended in a decisive victory for the allies.
Following the landing at Normandy the Americans contributed greatly to the outcome of the war, with dogged fighting in the Battle of the Ardennes and the Battle of the Bulge resulting in Allied victories against the Germans despite overwhelming odds. The battles took a heavy toll on the Americans, who lost 19,000 men during the Battle of the Bulge alone. The allied bombing raids on Germany increased to unprecedented levels after the D-Day invasion, with over 70% of all bombs dropped on Germany occurring after this date. Germany was flattened, the country was physically and emotionally rubble. On 30 April 1945, with Berlin completely overrun with Russian forces and his country in tatters, Adolf Hitler committed suicide. On 8 May 1945 the war with Germany was over, following their unconditional surrender to the Allied forces.
From a modest contribution in troops at the beginning of the campaign in Europe, by the end of the war approximately 66% of all allied divisions in Western Europe were American.
Battle against Japan
Due to the United States commitment to defeating Hitler in Europe, the first years of the war against Japan was largely a defensive battle with the U.S. Navy attempting to prevent the Japanese Navy from asserting dominance of the Pacific region. Initially Japan won the majority of its battles and did so with frightening speed. Japan quickly defeated and set up strong bases in Guam, Thailand, Malaya, Hong Kong, Papua New Guinea, Indonesia and Burma. This was done virtually unhindered and with quicker speed that the German Blitzkrieg of the early stages of the war. This was an important period for Japan as they had only 10% of the homeland industrial production capacity of the United States.
The turning point is this period was the Battle of Midway in June 1942. The United States Navy had broken the Japanese communication codes which allowed it to strategically position its ships in order to deliver a comprehensive defeat to the Japanese Navy. Following this the Americans began fighting towards China where they could build an airbase suitable to commence bombing of mainland Japan with its B-29 Superfortress fleet. The Americans began by selecting smaller, lesser defended islands as targets as opposed to attacking the major Japanese strongholds. During this period they inadvertently triggered what would become their most comprehensive victory in the entire war.
After defeating Japanese troops and landing in the Marianas Islands, the Japanese retaliated by sending 6 Aircraft carriers carrying 430 planes to counter attack. The battle that ensued on 19 June 1944 became known as the "Marianas Turkey Shoot". The American Navy pilots shot down 369 of the 430 Japanese bombers, fighters and dive bombers, and heavily wounded many others. Only 36 Japanese aircraft remained operational after this battle, or around 8%.
The pacific war became the largest naval conflict in history. The American Navy emerged victorious after at one point being stretched to almost breaking point with almost complete destruction of the Japanese Navy in this period. The American forces were now poised for an invasion of the Japanese mainland itself, in order to force the Japanese into unconditional surrender. The decision to use nuclear weapons to end the conflict has become one of the most hotly debated topics of the war. Supporters of the bombs accurately point out that an invasion would have cost enormous numbers of lives, as the battle of Okinawa showed where more people perished than both of the bombs put together. Supporters also point out that a conventional fire bombing campaign would have caused enormous civilian casualties, as the bombing of Tokyo had done. Those against the bomb argue that a military demonstration should have taken place, or that footage of the test bomb in Los Alamos should have been sent to the Japanese along with a demand for surrender. All hypotheticals aside the first bomb dropped on Hiroshima on 6 August 1945, and the Japanese were completely shocked. The second bomb dropped on Nagasaki on 9 August along with a bluff that there was plenty more where that came from. On 15 August 1945 the Japanese surrendered unconditionally and the war was over. The end came about without a bloody invasion, and it occurred as swiftly as the Americans had planned.
 Cold War beginnings and the Twentieth Century Civil Rights Movement (1945–1964)
Following World War II, the United States emerged as one of the two dominant superpowers. The U.S. Senate, on December 4, 1945, approved U.S. participation in the United Nations (UN), which marked a turn away from the traditional isolationism of the U.S. and toward more international involvement. The post-war era in the United States was defined internationally by the beginning of the Cold War, in which the United States and the Soviet Union attempted to expand their influence at the expense of the other, checked by each side's massive nuclear arsenal and the doctrine of mutual assured destruction. The result was a series of conflicts during this period including the Korean War and the tense nuclear showdown of the Cuban Missile Crisis. Within the United States, the Cold War prompted concerns about Communist influence, and also resulted in government efforts to encourage math and science toward efforts like the space race.
In the decades after the Second World War, the United States became a dominant global influence in economic, political, military, cultural and technological affairs. Following the collapse of the Soviet Union, it stands today as the sole superpower. The power of the United States is nonetheless limited by international agreements and the realities of political, military and economic constraints. At the center of middle-class culture since the 1950s has been a growing obsession with consumer goods.
John F. Kennedy was elected President in 1960. Known for his charisma, he was the only Catholic to ever be President. The Kennedys brought a new life and vigor to the atmosphere of the White House. During his time in office, the Cold War reached its height with the Cuban Missile Crisis in 1962. He was assassinated in Dallas, Texas, on November 22, 1963.
Meanwhile, the American people completed their great migration from the farms into the cities, and experienced a period of sustained economic expansion. At the same time, institutionalized racism across the United States, but especially in the American South, was increasingly challenged by the growing Civil Rights movement and African American leaders such as Martin Luther King, Jr. During the 1960s, the Jim Crow laws that legalized racial segregation between Whites and Blacks came to an end.
 Cold War (1964–1980)
The Cold War continued through the 1960s and 1970s, and the United States entered the Vietnam War, whose growing unpopularity fed already existing social movements, including those among women, minorities and young people. President Lyndon Johnson's Great Society social programs and the judicial activism of the Warren Court added to the wide range of social reform during the 1960s and 70s. The period saw the birth of feminism and the environmental movement as political forces, and continued progress toward Civil Rights.
In the early 1970s, Johnson's successor, President Richard Nixon brought the Vietnam War to a close, and the American-backed South Vietnamese government collapsed. The war cost the lives of 58,000 American troops and millions of Vietnamese. Nixon's own administration was brought to an ignominious close with the political scandal of Watergate. The OPEC oil embargo and slowing economic growth led to a period of stagflation under President Jimmy Carter as the 1970s drew to a close.
 End of the Cold War (1980–1988)
Ronald Reagan produced a major realignment with his 1980 and 1984 landslides. In 1980 the Reagan coalition was possible because of Democratic losses in most social-economic groups.
"Reagan Democrats" were those who usually voted Democratic but were attracted by Reagan's policies, personality and leadership, notably his social conservatism and hawkish foreign policy.
In foreign affairs bipartisanship was not in evidence. The Democrats doggedly opposed the president's efforts to support the Contras of Nicaragua. He took a hard line against the Soviet Union, alarming Democrats who wanted a nuclear freeze, but he succeeded in growing the military budget and launching a very high-tech "Star Wars" missile defense system that the Soviets could not match. When Mikhail Gorbachev came to power in Moscow many conservative Republicans were dubious of the friendship between him and Reagan. Gorbachev tried to save Communism in Russia first by ending the expensive arms race with America, then (1989) by shedding the East European empire. Communism finally collapsed in Russia in 1991.
After the fall of the Soviet Union, the United States emerged as the world's sole remaining superpower and continued to involve itself in military action overseas, including the 1991 Gulf War. Following his election in 1992, President Bill Clinton oversaw the longest economic expansion in American history, a side effect of the digital revolution and new business opportunities created by the Internet (see Internet bubble).
At the beginning of the new millennium, the United States found itself attacked by Islamist terrorism, with the September 11, 2001 attacks on the World Trade Center and The Pentagon orchestrated by Osama bin Laden. Another flight, Flight 93, crashed in Pennsylvania near a forest.
In response, under the administration of President George W. Bush, the United States (with the military support of NATO and the political support of most of the international community) invaded Afghanistan and overthrew the Taliban regime, which had supported and harbored bin Laden. More controversially, President Bush continued what he dubbed the War on Terrorism with the invasion of Iraq by overthrowing and capturing Saddam Hussein in 2003. This second invasion proved to be unpopular in many parts of the world and helped fuel a global wave of anti-American sentiment.
The presidential election in 2000 was one of the closest in American history, and helped lay the seeds for political polarization to come. In August 2005, Hurricane Katrina flooded parts of the city of New Orleans and heavily damaged other areas of the gulf coast, including major damage to the Mississippi coast. The preparation and the response of the government were criticized as ineffective and slow. As of 2006, the political climate remains polarized as debates continue over partial birth abortion, federal funding of stem cell research, same-sex marriage, immigration reform and the ongoing war in Iraq.
By 2006, rising prices saw Americans become increasingly conscious of the nation's extreme dependence on steady supplies of inexpensive petroleum for energy, with President Bush admitting a U.S. "addiction to oil." The possibility of serious economic disruption, should conflict overseas or declining production interrupt the flow, could not be ignored, given the instability in the Middle East and other oil-producing regions of the world. Many proposals and pilot projects for replacement energy sources, from ethanol to wind power and solar power, received more capital funding and were pursued more seriously in the 2000s than in previous decades.
- ^ "Paleoamerican Origins". 1999. Smithsonian Institution. Accessed 2 May 2006.
- ^ Diamond, Jared. Guns, Germs, and Steel, pages 99-100. W.W. Norton and Company, New York, 1999 paperback.
- The American Pageant: A History of the Republic (12th Ed.), Bailey, Thomas A., Cohen, Lizabeth, and David M. Kennedy. (2006).
- John Mack Faragher. The American Heritage Encyclopedia of American History (1998)
- John A. Garraty and Eric Foner, eds. The Reader's Companion to American History. (2000)
- Steven M. Gillon and Cathy D. Matson. The American Experiment: A History of the United States, 2nd ed. (2006)
- Johnson, Paul A History of the American People, Perennial, 1999. ISBN 0-06-093034-9
- David C. King. Children's Encyclopedia of American History (2003)
- Schweikart, Larry and Michael Allen. A Patriot's History of the United States: From Columbus's Great Discovery to the War on Terror (2007)
- George Tindall and David Shi. America: A Narrative History, Seventh Edition, (2006)
- Steve Wiegand. U.S. History for Dummies (2001)
- Zinn, Howard. A People's History of the United States, Perennial, 2003. ISBN 0-06-052837-0
 External links