For the third straight year, the Lincoln Memorial on the Mall was the most visited of the monuments and memorials in Washington in 2011. The memorial to the 16th president drew an estimated 6 million visitors that year, according to the National Park Service. (Associated Press)

For the third straight year, the Lincoln Memorial on the Mall was the most visited of the monuments and memorials in Washington in 2011. The memorial to the 16th president drew an estimated 6 million visitors that year, according to the National Park Service. (Associated Press)