The most memorable one is probably that of the unconditional surrender signed by the Japanese on September 2, 1945 on SS Missouri. (No, it was not the Emperor who signed it on Japan's behalf as President Obama once said, but by the Foreign Minister, Mamoro Shigemitsu and General Umezu. While the Emperor remained in place, there was an unquestionable regime change during a prolonged American occupation. One cannot really argue that Japan is not a better place for that.
Moving backward into history, today is the 170th anniversary...