It can seem like every few months someone is completing a feat of running that reaches new heights of toughness. Maybe it's Nedd Brockmann running across Australia. Maybe it's the Mont-Blanc Ultra-Trail. Aaron Crook did the infamous Marathon des Sables and now he's found something extreme in a different way. He's running across the Arctic. This might be the coldest race on earth.

Featured: Aaron Crook, Australian ultra marathon runner.

Subscribe to the ABC Sport Newsletter