On this day in 1920, Polish forces successfully forced the Russians to withdraw from Warsaw at the Battle of Warsaw, the decisive battle of the Polish–Soviet War.
On this day in 1942, Japanese forces attacked the Australian base at Milne Bay on the eastern tip of New Guinea.
On this day in 1989, the Voyager 2 spacecraft made its closest approach to Neptune and provided definitive proof of the existence of the planet's rings.