John Middendorf  is a big wall rock climber, who achieved worldwide recognition in the rock climbing world when he climbed the East Face of Great Trango Tower in Pakistan with Xavier Bongardin 1992. As a lightweight, two man team, they were the first to climb the 5000 foot vertical rock face of Great Trango Tower to the summit and make it down alive. (The eastern face of Great Trango Tower was previously climbed by a team of Norwegians, who died on the descent).

The climb is considered a very difficult big wall, and required 15 days and nights to climb and three days to descend, using portaledges designed and constructed by Middendorf in his shop (A5 Adventures, Inc.)