The first Colorado ski resort built after passage of the Environmental Protection Act (1969) incorporated runs, lifts, and facilities that purport to caress rather than scar the terrain. Runs were not totally cleared of trees but made to go around and through them. High-speed quad chair lifts and gondolas whisk skiers up the slopes day and night, as thirteen trails are lit until 9:00 p.m. The Keystone complex now includes Arapahoe Basin Ski Area (1946), North America's highest lift-served area, with enough snow for skiing into May. This comprehensive, single-owner resort has developed related resort and residential areas, including a golf course designed by Robert Trent Jones, Jr. With few older buildings to consider, Keystone Resort's design opportunities have been wide open, and it is a well-planned resort. The Keystone Conference Center (1989, Michael Barber Architecture), a 56,000-square-foot convention center trying to hide in a grove of lodgepole pine, is sheathed in “aspen tree gold” precast concrete panels. The Keystone Science School (1880s; 1976), a rustic campus of old log and frame cabins lining the Keystone rail grade, is an informal setting for the study of the environment and field trips into the spectacular surrounding mountains.