Sociologists and cultural anthropologists would analyze the institutions and group behavior of the various peoples who constitute the Middle East. Getting back to more practical matters, one must look to the recent history of the Middle East to explain what is happening there. The Middle East's geography has contributed to the diversity of its inhabitants. Nature did not endow the Middle East as lavishly as North America or Europe. Backgammon, chess, polo, and playing cards came to the West from the Middle East. Exploitation of Middle Eastern oil did not start until the twentieth century; it became large scale only after 1945. Middle Easterners have known conquest, outside domination, and a continuing exchange of people and animals with both the East and the West throughout their history. Frequent invasions have brought new races and folkways into the Middle East. The result is a vast mosaic of peoples, a living museum of physical types, belief systems, languages, and cultures.