National September 11 Memorial and Museum is a monument in New York City honoring the victims of the terrorist attacks of Sept. 11, 2001. It is also known as the 9/11 Memorial. On that day, terrorists hijacked four commercial airliners. They flew two of the planes into the twin towers of the World Trade Center in New York City. They crashed one plane into the Pentagon Building near Washington, D.C. Another plane crashed in a field in Pennsylvania. Nearly 3,000 people were killed. See September 11 terrorist attacks .
The 9/11 Memorial stands on the site of the former World Trade Center towers. The American architect Michael Arad and the American landscape designer Peter Walker designed the memorial. They named it “Reflecting Absence.” Twin reflecting pools lie in the footprints of the two towers. Waterfalls cascade into the pools. The site also includes a grove of swamp white oak trees. The names of people who died in the attacks are inscribed on bronze panels surrounding each pool. The names include people who died at the World Trade Center and at the Pentagon; the passengers and crews from the hijacked planes; and rescue personnel who died when the towers collapsed. The names also include victims of a separate attack on the World Trade Center in 1993.
The memorial opened to the public on Sept. 11, 2011, the 10th anniversary of the attacks. The National September 11 Memorial Museum opened on the site in May 2014. The museum’s main exhibition space lies 70 feet (21 meters) below street level. Its features include concrete and steel remnants of the twin towers and personal mementos from many of the people killed in the attacks. Its multimedia exhibits provide information on the towers, the terror attacks, rescue and recovery efforts, and the lives of many of the victims.
