The Pentagon Memorial honors the 184 people killed at the Pentagon in the September 11, 2001 terrorist attack. Opened in 2008, it consists of 184 illuminated memorial units — one for each victim — arranged in the shape of the aircraft's flight path. Each unit is a stainless steel bench positioned over a shallow reflecting pool.
The memorial is open 24 hours and is free to visit. It sits on the southwest corner of the Pentagon grounds, a short walk from the Pentagon Metro station.