These are the Marine Barracks on 8th Street SE. The buildings are among the oldest in Washington, established in 1801, and survived the War of 1812 as the British didn't burn them due to the bravery of the Marines they had fought. These barracks are also the oldest post in the US Marine Corps and home to the Commandant of the Marine Corps. It was tough to take a picture as there were guards everywhere and I felt a bit conspicuous, but this is what I managed to get.