Loads of skiing fanatics reckon the World Heli Challenge is the most legendary freeriding and freeskiing event on the planet.
The competition's organisers invite the world's most extreme snowboarding and skiing elite to compete head to head in the peaks of Mount Cook National Park.
It started back in 1995 in New Zealand, but it stopped in 2001 and it started again in 2009.
You can only get to the competition in a helicopter, and it's done over 10 days to allow for perfect weather and snow conditions.
The Extreme Day, as you can see in this pic of Luke Potts from Great Britain, does what it says on the tin... it's EXTREME MAN!
And here Luke actually loses his skiis as he hurtles down a cliff face... whatever you do, don't try this at home!