- 1189 Holy Roman Emperor Frederick I Barbarossa and 100,000 crusaders depart Regensburg for the Third Crusade
- 1751 Pennsylvania Hospital founded by Dr. Thomas Bond and Benjamin Franklin
- 1924 Daimler-Motoren-Gesellschaft and Benz & Cie begin their first joint venture (later merge into Mercedes-Benz)
- 1995 In New York City, more than 170 countries decide to extend the Nuclear Nonproliferation Treaty indefinitely and without conditions.
- 2015 India's poulation officially reaches 1 billion - Astha Arora named India's billionth baby
Waltz introduced into English ballrooms. Some observers consider it disgusting and immoral.
On May 11, 1812