The human icicles: Climbers tackle the world's hardest climb

This is the chilling moment two daredevils scale a 450ft waterfall covered in dangling icicles while upside down.
Will Gadd, 44, and Tim Emmett, 37, spent two weeks meticulously plotting their ascent of the notoriously tricky Helmcken Falls in Canada - ominously dubbed the world's hardest climb.
They had to battle deadly ice spray - which could freeze them to death in minutes - temperatures as low as minus 25C and the knowledge that one mistake would send them plunging into a 100ft deep ice hole below.

After four hours of constant, problem-free climbing the pair successfully reached the summit to become the world's first to conquer the falls.
Mr Gadd said they had to use sheer brute force to overcome the tricky 20ft icicles dangling from the overhanging walls.
He said: 'It's like doing hundreds of pull-ups on icicles to get to the top. By the end I'm not sure if we or the waterfall won.
'There was so much to deal with - getting covered in spray and turned into human popsicles, the huge icicles, the cold - the list is endless.
'The overhang behind the actual waterfall is extreme and means you are often climbing almost horizontally - it is like climbing along the underside of a

At over 450ft, the falls in Wells Grey Provincial Park, Canada, is one of the fiercest in the world - continuing to flow even in the depths of winter when temperatures dip well below freezing.
Its unique combination of challenges makes it one of the most difficult - and spectacular - climbs in the world.
Tim Emmett, from London, said: 'There's always debate about the true hardest climb in the world but I think all climbers would agree this is easily the most difficult.
'As you can imagine, we took our time and enjoyed the view once at the top - I think we had earned it.'
Mr Gadd added: 'There is literally no other ice in the world that is as difficult as this to climb.

'The spray ice also appears to create a cone that surrounds the water as it is in mid-air falling into the plunge pool. Over time this grows to be more than 100ft in height.

'It is quite frightening to think about what would have happened had we fallen in. It would be like plummeting into lava - you simply wouldn't be likely to live.'