9/11 memorial

The Tribute in Light illuminates the sky in New York on the 12th anniversary of the September 11, 2001 attacks. The tribute, an art installation of the Municipal Art Society, consists of 88 searchlights placed next to the site of the World Trade Center creating two vertical columns of light.

Timothy Clary/AFP/Getty Images

The Tribute in Light illuminates the sky in New York on the 12th anniversary of the September 11 2001 attacks. The tribute, an art installation of the Municipal Art Society, consists of 88 searchlights placed next to the site of the World Trade Center, creating two vertical columns of light

A man walks through the 9/11 Empty Sky memorial at sunrise across from New York's Lower Manhattan and One World Trade Center in Liberty State Park in Jersey City, New Jersey.

Gary Hershorn/Reuters

A man walks through the 9/11 Empty Sky memorial at sunrise across from New York’s Lower Manhattan and One World Trade Center in Liberty State Park in Jersey City, New Jersey.

A girl plants some of the 3000 flags placed in memory of the lives lost in the September 11, 2001 attacks, at a park in Winnetka, Illinois

Reuters/Jim Young

A girl plants some of the 3,000 flags placed in memory of the lives lost in the September 11 2001 attacks, at a park in Winnetka, Illinois, US