Efforts during the 1960s and 1970s explored the other faces of El Capitan, and many of the early routes are still popular today. Among the early classics are Salathé Wall (1961, Royal Robbins, Chuck Pratt and Tom Frost) on the southwest face, and the North America Wall (1964, Royal Robbins, Yvon Chouinard, Chuck Pratt and Tom Frost) on the southeast face. Also climbed in the 1960s are routes such as: Dihedral Wall (1962, Ed Cooper, Jim Baldwin and Glen Denny); West Buttress (1963, Layton Kor and Steve Roper); and Muir Wall (1965, Yvon Chouinard and TM Herbert).