Norseman Xtreme Triathlon, live.

Off a ferry ramp at five in the morning

Two hundred and fifty athletes jump into a Norwegian fjord in the dark, and the ones who finish do it on a mountain top.

Norseman is the original extreme triathlon and still the hardest to explain to anyone who has not seen it. The day begins at five in the morning with a jump from a car-ferry ramp into 13-degree water in the Hardangerfjord at Eidfjord. The bike leg climbs out of the fjord and crosses the Hardangervidda plateau; the marathon runs to Gaustablikk and then up Zombie Hill and the boulder field to the summit of Gaustatoppen at 1,883 metres, where the first 160 athletes to make the cut-off are allowed to finish and earn the black T-shirt.

Every athlete must bring their own support crew, which is why Norseman generates more tracking per starter than almost any race in the world: the crew is driving ahead all day, and the only thing they need is to know where their athlete actually is. Livebib puts swim, bike and run on one map with the athlete on it, transitions marked, and an arrival estimate for the next point that updates all day.