Heroic Hugh Herr enjoys nothing more than scaling a cliff - even though both his legs were amputated after a disastrous climbing expedition when he was a teenager.
As if conquering a 200ft rock face wasn't hard enough, one of his prosthetic legs fell off during his latest climb - but he calmly waited for it to be roped back up to him before making it to the top.
Mr Herr runs a lab making bionic legs at Massachusetts Institute of Technology, and insists artificial limbs are an advantage.
Brave Hugh Herr climbs a 200ft rock face, using his prosthetic legs to steady himself
Halfway to the top, one false move could be deadly for Hugh
Mr Herr makes full use of his prosthetic legs as he pulls himself higher
Hugh prepares his equipment before taking on his mammoth task
Hugh Herr, second left, with Who Says I Can't presenter Jothy Rosenberg, centre, and film crew