The US capital Washington is separated from the Arlington Air Force Base only by the Potomac River. Here, a foundation set up specifically for this purpose raised a widely visible Air Force Memorial in commemoration of the veterans and fallen airmen who served in the American Air Force. The three spires soar skyward in a taper to heights of over 80m and are made of stainless steel plated reinforced concrete. Designed by James Ingo Freed, a partner of I.M. Pei who died in 2005, their form mimics the contrails of jets streaking upward in "bomb burst" formation.