The 7 July 2005 London bombings (also called the 7/7 bombings) were a series of coordinated terrorist bomb blasts that targeted London's public transport system.. At 8:50 a.m., three bombs exploded within fifty seconds of each other on three London Underground trains. A fourth bomb exploded on a bus nearly an hour later at 9:47 a.m. in Tavistock Square. The bombings killed 52 commuters and the four suicide bombers and injured 700.