1752: Britain and the British Empire (including the American colonies) adopt the Gregorian calendar (no Sept 3 – Sept 13)

1936: 1st prefrontal lobotomy in America performed by Walter Freeman and James W. Watts at George Washington University Hospital in Washington D.C.

1939: World’s 1st practical helicopter, the VS-300 designed by Igor Sikorsky takes (tethered) flight in Stratford, Connecticut

1949: India’s Constituent Assembly adopts Hindi as an official language. Celebrated today as Hindi Day.

1956: IBM introduces the RAMAC 305, 1st commercial computer with a hard drive that uses magnetic disk storage, weighs over a ton

1960: Iraq, Iran, Kuwait, Saudi-Arabia and Venezuela form the Organization of Petroleum Exporting Countries (OPEC)

2020: Astronomers report possible sign of life on Venus, after detecting phosphine in planets’s atmosphere by telescope

2021: 1 in 500 Americans have died of COVID-19 as the nation’s known death toll reaches 663,913 (Johns Hopkins)

Source: Onthisday.com