In the 1880s, as the European powers were carving up Africa, King Leopold II of Belgium seized for himself the vast and mostly unexplored territory surrounding the Congo River. Carrying out a genocidal plundering of the Congo, he looted its rubber, brutalized its people, and ultimately slashed its population by ten million—all the while shrewdly cultivating his reputation as a great humanitarian. Heroic efforts to expose these crimes eventually led to the first great human rights movement of the twentieth century, in which everyone from Mark Twain to the Archbishop of Canterbury participated.