Visitors to the National September 11 Memorial walk below the rising towers 1 World Trade Center, left, and 4 World Trade Center, Monday, Sept. 10, 2012 in New York. Tuesday will mark the eleventh anniversary of the attacks of Sept. 11, 2001.
Families and friends of victims lost on Sept. 11, 2001, will gather at ground zero, the Pentagon and a field in Shanksville, Pa., to honor and remember those lost 11 years ago.
