I always thought that because of the wind patterns in the balloon races they
start
at one point, then fly several hundred miles and land someplace else.
but here...
http://www.cashfoundry.com/vm10.htm
there is a short time lapse movie and most of them come back to the place
from which they started.
It is also amazing how some 'bounce' up and down during flight, looks like
at
very small diferences of height above the ground, the winds can be flying
at totally different directions.