The highway pattern helps to identify rapidly growing Austin, the state capital (center of the photograph). Dark, serpentine Lake Travis west of Austin is part of the Colorado River that winds its way through downtown. Visible are the runway of Bergstrom Air Force Base southeast of Austin; part of Interstate Highway 35 entering Austin from the south; and the north-south-trending Balcones escarpment passing through the western part of the city. The escarpment denotes a dramatic topographic change in the landscape—gently rolling plains east of the escarpment and dissected, hilly terrain west of the escarpment. Clouds obscure agricultural lands east of Austin.