On February 6, 2004, an explosion struck a metro train in Moscow, killing at least 41 people and injuring more than 150 others. The blast went off on board a car traveling between the Paveletskaya and Avtozavodskaya stations, near the center of the capital. The explosion -- identified as a suicide bombing -- started a large fire, complicating rescue efforts. Just six months later, the Moscow metro would be struck again by another deadly suicide attack. (11 PHOTOS)