Associated Press

On Nov. 21, 1789, North Carolina became the 12th state to ratify the U.S. Constitution.

In 1967, President Lyndon B. Johnson signed the Air Quality Act.

In 1973, President Richard Nixon’s attorney, J. Fred Buzhardt, revealed the existence of an 18 1/2-minute gap in a White House tape recording related to Watergate.

In 1979, a mob attacked the U.S. Embassy in Islamabad, Pakistan, killing two Americans.

In 1995, Balkan leaders meeting in Dayton, Ohio, initialed a peace plan to end 3 1/2 years of ethnic fighting in Bosnia-Herzegovina.

In 2012, Israel and the Hamas militant group in Gaza agreed to a cease-fire to end eight days of the fiercest fighting in nearly four years.

In 2017, Zimbabwe’s 93-year-old president Robert Mugabe resigned.