In the Americas, pre-Columbian peoples had built a large and varied civilization, including the Aztec Empire, the Inca civilization, the Maya civilization and its cities, and the Muisca. The European colonization of the Americas began during the early modern period, as did the establishment of European trading hubs in Asia and Africa, which contributed to the spread of Christianity around the world. The rise of sustained contacts between previously isolated parts of the globe, in particular the Columbian Exchange that linked the Old World and the New World, greatly altered the human environment. Notably, the Atlantic slave trade and the genocide of Native American peoples began during this period. Turkey conquered Southeastern Europe, and parts of the West Asia and North Africa. Russia reached the Pacific coast in 1647 and consolidated its control over the Russian Far East in the 19th century. The Great Divergence took place as Western Europe greatly surpassed China in technology and per capita wealth.