It's a triathlon across the Highlands, starting with a swim in the cold waters of the Firth of Forth and ending with a run up and down from the snow covered summit of Ben Nevis. (Yes, it is nearly summer in the UK but you wouldn't know it!)
Working hours are 5am to 2am on what is sure to be an epic day.
http://www.ratracecitytosummit.com/