Big Wall Aid Climbing
Aid Climbing (or Big Wall Climbing in the USA) is the art of climbing seemingly impossible rock faces by placing gear and using it to progress (rather than just using the rock for progression). Therefore aid placements only need to hold bodyweight though it is obviously wise to have a piece in now and again that will hold a fall as many aid placements are very marginal to say the least. Although aid climbing in the early days used pegs almost exclusively, nowadays the emphasis is on using clean aid such as nuts and cams which don't scar the rock.
For more information on aid climbing please see our Big Wall Aid Climbing Page.