The 7 July 2005 London bombings, sometimes referred to as 7/7, were a series of coordinated terrorist suicide bomb attacks in central London which targeted civilians using the public transport system during the rush hour. The explosions were caused by homemade organic peroxide-based devices packed into backpacks. The bombings were followed two weeks later by a series of attempted attacks that failed to cause injury or damage. The 7 July attacks occurred the day after London had won its bid to host the 2012 Olympic Games, which had highlighted the city's multicultural reputation.