Associated Press

On Sept. 11, 1789, Alexander Hamilton was appointed the first U.S. Secretary of the Treasury.

In 1936, Boulder Dam, later renamed the Hoover Dam, began operation as President Franklin D. Roosevelt in Washington signaled the startup of the dam’s hydroelectric generator.

In 1941, groundbreaking took place for the Pentagon.

In 1954, the Miss America pageant made its network TV debut on ABC.

In 1973, Chilean President Salvador Allende died during a violent military coup led by General Augusto Pinochet.

In 2001, nearly 3,000 people were killed as 19 al-Qaida hijackers seized control of four jetliners, sending two of the planes into New York’s World Trade Center, one into the Pentagon in Arlington, Virginia, and the fourth into a field in western Pennsylvania.