INTERNATIONAL FALLS, MN - The Arrowhead 135 started Monday. Race organizers say it's one of the 50 hardest races on earth.
Here's a look at Monday morning's race start which officially began at 7 a.m.
It's a 135 mile race on the Arrowhead State Snowmobile Trail.
People run, bike or cross country ski from International Falls to Fortune Bay Casino.
Organizers say the leaders are expected to finish around 9 p.m. Monday.