Granite quarrying started at Stone Mountain in the 1830s, but became a major industry following the completion of a railroad spur to the quarry site in 1847. This line was rebuilt by the Georgia Railroad in 1869. Over the years, Stone Mountain granite was used in many buildings and structures, including the locks of the Panama Canal, the steps to the East Wing of the United States Capitol and the Imperial Hotel in Tokyo. In recent years, granite suppliers in Georgia sent stone samples cut from Stone Mountain to the group responsible for planning the Martin Luther King Jr. Memorial in Washington, D.C.; the foundation later chose to use granite imported from China. Quarrying during earlier periods also destroyed several spectacular geological features on Stone Mountain, such as the Devil's Crossroads, which was located on top of the mountain.