Ed Stewart makes radio history this week by climbing Britain's two highest peaks - Mount Snowdon and Ben Nevis - for the Cystic Fibrosis Trust. The Trust runs regular Ben Nevis climbs and occasional Three Peaks walks, taking in Snowdon, Scafell Pike and Ben Nevis - but this is the first time climbs like this have been broadcast live. Ed starts his week by tackling Snowdon. Join him along the Pyg Path as he struggles to the 3,560ft summit.