1807 – Former U.S. Vice President Aaron Burr is acquitted of treason. He was accused of plotting to annex parts of Louisiana and Spanish territory in Mexico to establish an independent republic. Burr had earlier killed Alexander Hamilton in a duel.
1939 – German forces, under the control of Adolf Hitler, invades Poland, signaling the start of World War II.
1972 – Bobby Fischer defeats Russian Boris Spassky in the “Match of the Century” to become the first American to win the World Chess Championship.
1985 – Wreck of the RMS Titanic is found by a joint U.S.-French expedition about 400 miles east of Newfoundland in the North Atlantic, some 13,000 feet below the surface.