We'll begin with the extreme version of the home climbing wall. The 36½-foot-high climbing wall in this private home spans four stories. The design process was a collaboration between the homeowner, the architects at Krannitz Gehl and Entre Prises Climbing Walls (which makes the walls for REI and big climbing clubs). "When we were planning the entry, the owner, who is an avid climber and has lots of climbing friends, suggested it would be a great spot for a climbing wall," says architect Barry Gehl. "We contacted Entre Prises to coordinate in terms of the structure and support required." Also concerned with safety, the group collaborated on where to place the routes so as to avoid the danger of hitting the glass wall and the stair railings. Entre Prises then sculpted the wall and created routes from beginner to difficult, placing two self-arresting rappelling gears at the top accordingly.