9/11 Memorial opens in New York (41 images)

Robert Peraza, who lost his son Robert David Peraza, pauses at his son's name at the North Pool of the 9/11 Memorial during tenth anniversary ceremonies at the site of the World Trade Center in New York on September 11, 2011. UPI/Justin Lane/Pool

Families wait to visit the Memorial Pools on the tenth anniversary of the terrorist attacks on the World Trade Center on 9/11 at Ground Zero in New York City on September 11, 2011. UPI/John Angelillo

Families line up against the wall of the South Memorial pool during tenth anniversary ceremonies at the site of the World Trade Center September 11, 2011, in New York. UPI/Timothy A. Clary

A memorial pool is seen at the National September 11 Memorial at the World Trade Center site in New York, on September 11, 2011. UPI/Seth Wenig/Pool