1865

Four people were hanged in Washington, D.C. for conspiring with John Wilkes Booth to assassinate President Abraham Lincoln: Lewis Powell, David Herold, George Atzerodt and Mary Surratt, the first woman to be executed by the federal government.

1930

Construction began on Boulder Dam.

1990

The first “Three Tenors” concert took place as opera stars Luciano Pavarotti, Placido Domingo and Jose Carreras performed amid the brick ruins of Rome’s Baths of Caracalla.