http://en.wikipedia.org/wiki/List_of...y_death_ toll
Biggest is this:
20,000,000[6] 100,000,000[7][8][9][10][11] Taiping Rebellion China 1851 1864 14 Dungan revolt
20 to 100 million deaths in 14 years...
2,000,000
[36] 100,000,000
[37] European colonization of the Americas Americas 1492 1900 408 Colonization, disease, ethnic cleansing and war.
upto 100 millions...