On July 7, 2005, four suicide bombers attacked London's busy bus and subway system. Fifty-six people were killed and about 700 others were injured. Two weeks later four other men tried to carry out a similar attack, but this time the bombs failed to explode. In this News and Review story we'll look at the attacks, and at the men who carried them out. And we'll show you how they triggered the biggest police investigation in British history.