Flag Day in the United States
1285 – Forces led by Prince Trần Quang Khải of Vietnam's Trần dynasty destroyed most of the invading Mongol naval fleet in a battle at Chuong Duong.
1777 – The Second Continental Congress adopted the stars and stripes design for the flag of the United States (pictured).
1822 – In a paper presented to the Royal Astronomical Society, English mathematician Charles Babbage proposed a difference engine, an automatic, mechanical calculator designed to tabulate polynomial functions.
1944 – Second World War: The British Army abandoned its attempt to capture the German-occupied city of Caen.
1966 – The Vatican formally abolished its 427-year-old list of prohibited books.