It is traditionally believed that the first Americans were Indians.

Columbus is believed to have discovered America.

Actually, Amerigo Vespucci discovered the continent of South America and it was later named after him.

The first successful English colony in North America was founded at Jamestown, Virginia, in 1607.

In 1620, the Pilgrim Fathers sailed for Virginia on a ship called the Mayflower.

In 1763, England gained control of North America east of the Mississippi. Soon afterward, England and its colonies were in conflict.

On April 19, 1775, fighting broke out in Lexington and the first shots in the America War of Independence were fired.

在 May 1775, the Second Continental Congress was held in Philadelphia.

On July 4,1776, Thomas Jefferson drafted the Declaration of Independence and its theory of politics is central to the Western political tradition.

In 1783, the British and the Americans signed the Treaty of Paris, and America won its independence.

Reason：the conflicts (mainly about the slavery) between the North and the South were growing.

On January 1, 1863, Lincoln issued the Emancipation Proclamation, which granted freedom to all slaves.

In 1865, Lee surrendered to General Grant of the Union army, and all other Confederate forces soon surrendered.

Slavery was completely abolished and America became a single, indivisible nation.

At the start of World War I, America took a neutral stance, later entered the war in 1917 with several reasons.

In January 1918, President Wilson proposed his Fourteen Points as the basis for peace negociation, but the U.S. Congress refused to ratify the treaty.

在 1929—1933， America had an economic depression. Roosevelt was elected President and introduced the "New Deal", helping the country get out of the depression.

In the early days of World War II, the U.S. government adopted a site-on-the-fence policy, and the American capitalists wanted to continue their profitable trade with the warring countries, including the aggressors.

在 1941, America declared war against Japan. In 1944, America dropped two atomic bombs on Hiroshima and Nagasaki. On August 14, Japan surrendered and World War II ended.

In April 1945, a conference was called in San Francisco to organize the United Nations. During World War II, the development of the America economy reached a higher stage.

The Cold War：In the spring of 1947, Pesident Truman declared the "Truman Doctrine", marking the begining of the Cold War. In 1949, the U.S. formed the North Atlantic Treaty Organization.

The Korean War(1950-1953), The Vietnam War(1954-1975), the war greatly weakened America and sharpened the country's internal contradictions.

Nixon：reestablishing U.S. relations with China and negotiating the first Stratebic Arms Limitation Treaty with the Soviet Union.(Watergate Scandal)

Reagan：called for tight money policy, leding to an increasing gap between rich and poor, and socoal welfare programs had been drastically curtailed. At the end of his administration, the nation was enjoying pod longenjoying s.

Bush：joined the war between Kuwait and Iraqi, leding to faltering economy.

Clinton：signed the North American Free Trade Agreement.

George W. Bush, son of the former President Bush, became the President of the U.S.

On September 11, 2001, the United States suffered the most devastating foreign attack ever against its mainland.