The 22nd and 24th president, Grover Cleveland is the only POTUS to serve two nonconsecutive terms, as well as the first to be married in the White House.

On April 14, 1865, actor John Wilkes Booth assassinated President Abraham Lincoln while he was watching Our American Cousin at Ford Theater in Washington, D.C.

Albert Einstein was a German-born physicist who developed the theory of relativity. He is considered the most influential physicist of the 20th century.

Arnold Schwarzenegger first gained fame as a body builder, using that as a launching point to become a huge Hollywood star and, later, the governor of California.

Ulysses S. Grant was U.S. general and commander of the Union armies during the late years of the American Civil War, and 18th president of the United States.

J.K. Rowling is the creator of the Harry Potter fantasy series, one of the most popular book and film franchises in history.

Barack Obama is the 44th and current president of the United States, and the first African American to serve as U.S. president. First elected to the presidency in 2008, he won a second term in 2012.

Former Massachusetts Governor Mitt Romney made a run for the Republican nomination in the 2008 presidential election, losing to John McCain. He made another run for the presidency in 2012, but was defeated by President Barack Obama.