The National September 11 Memorial / New York Architect: Michael Arad; landscape architect: Peter Walker, 2011. Walls of tears cascade down the huge footprints left where the twin towers once stood. (CC-by-SA which means anyone can freely use any size of this image anywhere, provided accompanied by the credit: Image: George Rex.)
The Tear Drop Monument was donated by the Russian people in tribute to those lost on 9/11. The names of those lost are inscribed in the base similar to the Vietnam Wall in DC. The walkway is lined with stones donated by those in remembrance of this day. The site is directly across from the Statue of Liberty, and looking at that skyline, you truly do see what's missing.