Australian PM Scott Morrison welcomed for week-long visit at the White House by US President Donald Trump
- Batman Day - 80th anniversary of the first Batman comic
- Rare Egyptian political protests take place against corruption in President Abdul Fattah al-Sisi's government in Tahrir Square, Cairo and elsewhere
- Researchers for SETI (Search for Extraterrestrial Intelligence) propose that aliens may have bugged earths co-orbitals (nearby orbiting rocks) in "The Astronomical Journal"
Students from 185 countries stage the world's largest-ever protest on climate change culminating in Manhattan rally led by Greta Thunberg
- The MOSAiC expedition, the greatest Arctic research expedition ever, sets sail from Norway, aims to stay trapped in ice for a year to study climate change
- Howard Cassady, American College Football Hall of Fame halfback (Heisman Trophy 1955; Detroit Lions), dies at 85
- Su Beng [Lim Tiau-hui], Taiwanese revolutionary, 'Father of Taiwanese Independence' (Taiwan’s 400-Year History), dies at 100