While lin­ger­ing is not rec­om­mend­ed for secu­ri­ty rea­sons, you should know it is the largest office build­ing in the world, and cov­ers 4 zip codes. (Army, Navy, Air Force and Depart­ment of Defense.Tours are avail­able by online reser­va­tion mad­er 14–90 days in advance. Wash­ing­ton Blvd side, where Flight 77 hit. Pho­tog­ra­phy is allowed at the memo­r­i­al, but is ”’not per­mit­ted”’ any­where else on the Pen­ta­gon ground­sA take pho­tos any­where else on site, and you may face a lengthy inter­ro­ga­tion by the Pen­ta­gon Police and will prob­a­bly be asked to delete the images. On a lighter note, the inte­ri­or court­yard is irrev­er­ent­ly referred to by employ­ees as Ground Zero, as it was the tar­get of a num­ber of Sovi­et mis­siles dur­ing the Cold War. There is no pub­lic park­ing at the Pen­ta­gon but it is about a 5‑minute walk from the Pen­ta­gon City Mall through a tun­nel.