Jon Golden, as told to Nina Strochlic, National Geographic:

T MINUS SIX MONTHS
Gearing up: I’ll be photographing a team of extreme adventurers mountain biking across the frozen Arctic Ocean in Canada. I’ll be on a snowmobile, which is still hard work, so I need to get in good shape. A few months before, I start running and doing core workouts. In the Arctic you can’t sit down if you’re tired—you have to keep moving or get in your sleeping bag. I also put in a request to my sponsors for some gear: a down-filled sleeping mat and gloves I can shoot with.

T MINUS TWO WEEKS
Essential packing list: Our camp in Auyuittuq is 50 miles from civilization in any direction, so I take everything I need for the 2.5-day February trip.
– Emergency beacon
– A satellite phone (which will be on for only two hours a day, so I go over safety protocols with my family beforehand)
– Macadamia nuts (they have the highest fat content)
– A toothbrush with pre-applied toothpaste
–  A dozen camera batteries. The cold zaps their power, so I keep them in my vest or sleeping bag.
– Two sets of long underwear