For many people, a camping trip is enough to get them sweating before theyve even put up a tent pole. But for these daredevil explorers, scaling cliffs and pitching tents at the height of more than 300 double decker buses. Hanging precariously in tents off a 4,000ft shear cliff face, these climbers are chasing the most dangerous big wall climbs ever attempted. The climbs can last for weeks and the explorers must set up tents on the edge of monstrous cliff faces to grab some much needed rest. They were taken by adventure photographer Gordon Wiltsie, 57, who risks his own life to capture thrill-seeking moments. He said: 'During this climb it was the Arctic spring so melting snow on both the summit and a ledge midway up the cliff constantly sent rocks and chunks of ice flying down. 'One the size of a car even came crashing down around us. Several times I came within inches of being hit which almost certainly would have been fatal. Falling objects are constantly on your mind and if you look carefully at the picture of the hanging tents, or Portaledges, you can see the camp was below an overhang for shelter. 'For serious big wall climbers simply being this far off of the ground isnt scary or dangerous in itself. And although the climb was hard enough that it was possible to take a big fall, the cliff was so steep there were a few ledges to hit and modern ropes are stretchy enough to absorb most of the impact. Camping in the Portaledges is a lot less scary and dangerous than it is climbing outside of them. Theyre pretty comfortable and you dont actually see the drop below. 'I find it similar to sleeping into a regular tent. Youre always harnessed into a separate anchor from the tent so I felt quite safe - unless I had to lean out to get food or supplies from our haul bags hanging outside. Mr Wiltsie, from Bozeman in Montana, added: 'Although rock climbing like this seems insane, dozens of similar trips take place in remote locations every year. And in places like the Alps or Yosemite National Park that are closer to home perhaps thousands are undertaken. Depending on the season it can be done anywhere in the world - I have also made a similar ascent in Queen Maud Land, Antarctica and other extreme locations in places such as the Himalayas and Africa. I was a mountaineering guide for many years but I have done big wall climbs only about half a dozen times. Im really excited about my summer exhibit of my work. The Mountain Light Gallery in California was established by the late Galen Rowell. Hes one of my own mentors and also widely considered to be the godfather of modern adventure photography. MO