The mongols is history's biggest land contiguous empire that grew under the leadership of Khan,and was made of nomadic people. It sprung from eastern Europe and spread all the way to the far east.
The Mongolians were an exception because they perfected the mail system,protected the silk road, and left a legacy of unified political units such as Russia and China.
Migration, trade, conquest, and pursuit of religious freedom.
Most native american deaths resulted from disease brought from the old world (Europe)
