A frame grab shows emergency vehicles on the scene outside King's Cross station in London July 7, 2005. A series of explosions rocked London's transport system at rush hour on Thursday morning, causing numerous casualties and leaving millions of passengers in shock, police said. The causes of the incidents -- which occurred one day after London was awarded the 2012 Olympics and as leaders of the Group of Eight rich nations met in Scotland -- were unknown but police said many of the city's underground stations were affected. People were seen streaming out of one underground station covered with blood and soot. Passengers were evacuated from stations across the capital, many in shock and with their clothes ripped to shreds, witnesses said. (Reuters Tv/Reuters)