This sign greets visitors at the entrance to the 9/11 Memorial.

9/11 Memorial Pools designed by Michael Arad, called "Reflecting Absence."

Search and rescue dogs at the 9/11 Memorial gift shop.

9/11 Memorial Donation box.

Families crowd around the South Pool at the World Trade Center Memorial plaza.

Unofficial souvenir books on 9/11 for sale in Lower Manhattan near the World Trade Center site.

The Memorial plaza and museum are still under construction on the 12th anniversary of the World Trade attacks.

9/11 commemorative bracelets for sale at the 9/11 Memorial store.

Flowers at the 9/11 Memorial pools.

Leaves designed after the ones found at the World Trade Center Memorial Plaza for sale at the 9/11 Memorial gift shop.

Motorcycle at the 9/11 Memorial Gift shop in Lower Manhattan.

Over 4.5 million visitors went to the 9/11 Memorial Plaza in its first year.