Free-running, or Parkour as it's also known, can be hazzardous at the best of times but how about doing it with no clothes on?
Champion free-runner Tim Shieff took to the London skyline to do just that for a series of incredible photographs shot by fellow athlete Jason Paul.
The series of photographs are called ‘Man & Mortar’ and show Tim jumping over rooftops and even on the tube. They are being sold to raise money for Jamie Oliver's Food Foundation.
Tim joined Wake Up London to tell us more.