- On this day in 1939, Igor Sikorsky's VS-300 world's first ever practical helicopter flew in a tethered test in Connecticut, America.
- On World War II today, German U-39 boat was attacked by British fleet in 1939.
Today in 1948 marked the UN Headquarters groundbreaking ceremony. Also in 1948 today, Hindi was adopted as the Indian official language by the Constituent Assembly of India making the date Hindi Day.
Also on this date, West Germany was rearmed by Western allies in 1950 while Nikita Khrushchev was made the Communist Party First Secretary of the Soviet Union in 1953.
Unmanned Luna-2 of Soviet Union became the first spacecraft to ever land on the moon's surface in 1959.
Jupiter's 13th satellite, Leda was discovered this day in 1974 by Charles Kowal.
On this day in 2001, the Historic National Prayer Service took place in Washington National Cathedral for 9/11 attack victims.
Also this day in 2017, the earliest zero symbol existence evidence was revealed by carbon dating in the Bodleian Library from a Bakhshali Pakistani manuscript going back third or fourth century.
On this day in 1965, Russian President Dmitry Medvedev was born, including American songwriter and rapper Nas in 1973 and British songwriter and singer Amy Winehouse in 1983.
On this day in 1901, 25th American President William Mckinley died eight days being shot in New York by an anarchist, including dancer pioneer Isadora Duncan in 1927 when her long scarf got ensnared on a car's rear wheel, American actress Grace Kelly in 1982 after a stroke and a car accident and American actor and dancer Patrick Swayze in 2009 from pancreatic cancer.
American NBA player Lebron James married Savannah Brinson on this day in 2013 while American film director John Carpenter divorced his wife of five years, Adrienne Barbeau in 1984.