After President McKinley was shot, Teddy Roosevelt became president and the first to have round the clock protection by the Secret Service. But why did it take Congress 25 presidencies and three assassinations to make that happen?

Less than two months into his presidency, JFK signed Executive Order 10924, formally creating the Peace Corps as an agency within the U.S. State Department. By the end of 1961, 750 inaugural Peace Corps volunteers had served in 13 countries.

As the southern states are succeeding, Lincoln begins his journey to Washington, D.C., but encounters fierce enemies along the way.

In 1743, Thomas Jefferson was born to one of the most powerful families in the most powerful of Britain's 13 North American colonies.