On September 11, 2009, the eighth anniversary of the September 11, 2001, terrorist attacks, a memorial that not only will honor those who died, but also will be a place where future generations can learn about the historical impact of that day, is scheduled to open on the site of the World Trade Center.

"This memorial is not for us. … It is for our children and grandchildren. It is so those who visit that sacred ground know what happened there and why so many people died to protect our freedoms," New York City Mayor Michael Bloomberg said at the unveiling of a design for a memorial called Reflecting Absence in January 2004.

Reflecting Absence will be a 16-acre site to honor those who died in the terrorist attacks at the World Trade Center, at the Pentagon, and on Flight 93 in Shanksville, Pennsylvania, as well as those who died in the February 26, 1993, bombing of the World Trade Center. In addition to this memorial, on-site memorials are planned for the Pentagon and the Flight 93 crash site.

Architects Michael Arad of New York and Peter Walker from Berkeley, California, designed the memorial, which also honors survivors and those who assisted in the rescue and recovery process.

Arad and Walker's design proposal called for "a space that resonates with the feelings of loss and absence that were generated by the destruction of the World Trade Center."

The proposed design features two large pools that encompass the footprints of the Twin Towers, surrounded by trees and waterfalls to block out noise from the city. The names of the 2,979 victims will be written along the edge of the pools. Visitors will enter through Memorial Hall, a quiet space that provides views of the waterfalls and pools.

The memorial will include a visitors center and an education center. A 9,000-square-meter interpretive museum will share stories from the attacks and tales of heroism.

The site will also feature a space for visitors to light a candle or hold a quiet memorial service. There will be an area for families of victims to gather and an area that will serve as a final resting place for unidentified remains from the World Trade Center.

The memorial will "encourage reflection and contemplation" as well as "evoke the historical significance" of September 11, according to the memorial program's guiding principles, written by the Lower Manhattan Development Corporation (LMDC). The memorial will "inspire and engage people to learn more about the events and impact" of the terrorist attacks.

The LMDC launched a design competition—the largest in history—to select a design for the memorial in April 2003. A 13-member jury of artists, family members of victims, government representatives, and area residents reviewed 5,201 submissions from 63 countries and 49 states before selecting Arad and Walker's design.

Preliminary work on Reflecting Absence began in March 2006. New York Governor George Pataki and New York City Mayor Michael Bloomberg released a report in June that establishes a plan for the building process, keeping it within an estimated $500-million budget. The plan is currently being reviewed, and a final design is expected to be adopted soon.