Without the aid of a vehicle, speed skating is one of the quickest ways on the planet for a person to move.
Top skaters can hit speeds of up to 60mph during races, as they fly around an icy track.
There are two types of speed skating - short-track and the longer, more traditional version.
Short-track can be a brutal event, with four skaters trying to squeeze around a 110m oval icy track, often hitting each other and falling over.
In fact, in 2002, one skater took gold in an event after all three of his rivals fell over in the final.
The longer version is much more graceful, and at times it's difficult to believe the skaters are moving as quickly as they are.
They fly around the 400m oval in less than half the time it would take to cover the same distance on a running track.