On September 11, 2006, the world marked the fifth anniversary of a deadly attack on the United States. On that day in 2001, a group of Al Qaeda terrorists flew three airliners into buildings in New York and Washington. A fourth hijacked plane crashed in a field in Pennsylvania. Almost 3,000 people, including 24 Canadians, were killed. In this News in Review story we'll look at how the attack, and the U.S. response, helped change our world forever.