An all terrain crane uses chains to both lift and lower materials as well as move them horizontally in a construction site. The main advantage is its ability to hoist heavy materials into the air and move them which would be difficult to move otherwise. Cranes have a long history being used by the Greeks and during the middle ages. These cranes were powered by livestock as they walked in a circle to power the lift.
All-terrain crane pictures
All-terrain crane video
http://www.youtube.com/watch?v=ib3c3lJfVAA