The mobility of people, goods, and ideas across the surface of the Earth.
http://www.youtube.com/watch?v=92N1kaYEYPw
The theme of movement helps geographers understand the relationship among places. Movement helps explain how people, goods, and ideas get from one place to another.
Why Do People Move?
Some people travel for their career.
Others move to be closer to family.
Some migrate to escape war, religious persecution, political reasons, work/economic and education.