December 27, 1831
Naturalist Charles Darwin embarks on his journey aboard the HMS Beagle, during which he will begin to formulate the theory of evolution.
December 29, 1890
In the final chapter of America’s long Indian wars, the U.S. Cavalry kills 146 Sioux at Wounded Knee on the Pine Ridge reservation in South Dakota.
December 30, 1922
In post-revolutionary Russia, the Union of Soviet Socialist Republics is established, comprising a confederation of Russia, Belorussia, Ukraine, and the Transcaucasian Federation.