A large crowd gather at the scene of the explosion on a busy road in downtown Nairobi, Kenya, Monday, May 28, 2012. An apparent explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-story building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/Sayyid Azim)