Visiting the Lincoln Memorial
Erected to honor Abraham Lincoln, the 16th President of the United States, it was completed in 1922, and features a stunning, neoclassical architectural style that is reminiscent of ancient Greek temples.
As with most of the memorials in Washington DC, the Lincoln Memorial is open 24 hours a day. While the public may visit at any time of day, the National Park Service Rangers, who administer the memorial, are on duty to answer any questions between 9:30 am and 11:30 pm each day. National Park Police officers make rounds through memorial park 24 hours a day.
http://www.nps.gov/linc/index.htm