On clear days, views from Clingmans Dome can reach Mount Mitchell, the highest peak in the eastern United States, 73 miles away in North Carolina's Black Mountains, and visibility can sometimes exceed 100 miles, though clouds and severe haze caused mainly by pollution can drastically reduce it. For decades, visitors have come to Clingmans Dome, the highest peak in the Smokies at 6,643 feet, to enjoy the panorama. The mountain was named for Thomas Lanier Clingman, one of several explorers who studied and measured North Carolina's mountains in the 1850s. Before the present concrete observation tower was completed in 1960, visitors climbed a wooden tower there, and workers were still finishing the ramp wall of the new tower in 1959.