One of the two black-clad arches at the Oklahoma City National Memorial. The 9:03 inscription refers to the time 1 minute after the detonation of the bomb which took 168 lives in and around the Alfred P. Murrah Federal Building on April 19th, 1995. A second arch, inscribed 9:01 sits facing this one at the opposite end of a reflecting pool.
For the technically inclined...