Policeman prepares to observe two-minute silence in memory of victims of London bombings next to site of bus bombing at Tavistock Square in central London. A policeman prepares to observe a two-minute silence in memory of the victims of the London bombings, next to a tarpaulin covering the site of the bus bombing at Tavistock Square in central London, July 14, 2005. The British capital led the tributes on Thursday as millions of people across Europe joined a two-minute silence to mark the July 7 London bombings that claimed at least 52 victims. REUTERS/Russell Boyce