Stephen Potter, a retired regional archaeologist for the service’s national capital region, cataloged some of the graffiti in the 1980s, noting “some that were extremely well executed.”

The National Park Service theorizes that a century-old sketch made by a worker in the Lincoln Memorial’s undercroft depicts Theda Bara, silent film’s first “Vamp.”

Forty-five feet below the Lincoln Memorial is art of a very different kind. On the pillars in the memorial's basement, where a visitor center is now under construction, is graffiti left behind by the workers who built the memorial to Abraham Lincoln more than a century ago.