The challenge is a 39.2km circular route that climbs all three mountains in the stunning countryside of the Yorkshire Dales - Whernside (736m), Ingleborough (723m) and Pen-y-ghent (694m). It is a one-day event and most walkers complete the route in 10-13 hours. But this challenge should not be taken lightly as the terrain is extremely varied involving some steep ascents and descents.