In 1868, the last unmapped region in the United States centered on what is now Grand Staircase-Escalante National Monument. Mapping began with John Wesley Powell’s second trip down the Colorado River in 1871. After he returned to Washington, D.C., another group of men led by Powell’s second in command, Almon Harris Thompson, returned to the region and spent five years filling the blank spot on the map. Even after the maps were completed, few people ventured into this harsh landscape. Scientists were the exception. Enticed by Powell’s reports, geologists like Clarence Dutton and G.K. Gilbert, and later Herbert Gregory, followed his example, advancing knowledge and their careers by studying the region’s remote interior. For what remains to be discovered, this magnificent landscape was made a national monument.