German Unity Day is the national day of Germany, celebrated on 3 October as a public holiday. It commemorates the anniversary of German reunification in 1990.
An alternative was the day the Berlin Wall came down: 9 November 1989. This was the day of the German Republic in 1918, and the defeat of Hitler's first coup in 1923.
However, 9 November was also the anniversary of the first large-scale Nazi-led pogroms against Jews in 1938 (Kristallnacht), so the day was thought inappropriate as a national holiday.