Soon after the attacks on the
World Trade Center plans were made to create a memorial to commemorate the victims of the tragedy. As early as in April 2003, a competition was launched by the Lower Manhattan Development Corporation for the design of a World Trade Center memorial. In total 5,201 submissions were made from 63 different countries.

Reflecting Pool
On January 6, 2004, a 13 member jury selected a design by architect Michael Arad and Peter Walker. The jury lauded the openness of the design, which was dubbed 'Reflecting Absence'.
The winning design was unveiled to the public on January 14, 2004. It consists of a 6 acre (2,5 ha) memorial plaza with a grove of 124 white oaks and two large illuminated reflecting pools. The pools, which mark the exact site of the former twin towers, are recessed and its walls form a series of cascading waterfalls. The names of the 2977 people who died on September 11 (including those who died in Pennsylvania and Washington, DC) as well as the victims of the 1993 bombing are inscribed around the edge of the waterfalls.
The memorial was inaugurated on September 11, 2011, exactly ten years after the terrorist attack, and opened to the public the following day.
The memorial plaza is built on top of a large transit hub to be completed in 2013. The hub is marked by a spectacular PATH entrance station created
by the celebrated Spanish architect Santiago Calatrava. An underground museum opened to the public on May 21, 2014. The museum assesses the implications and impact of 9/11. On display are artifacts from the Twin Towers. Multimedia displays and artifacts from the Twin Towers tell the story of the attack and its impact.
The memorial is now officially known as the 9/11 memorial, referring to the date of the terrorist attacks, which occurred on the 11th of September, 2001 (The American date format shows the month first, followed by the day).
An underground museum opened to the public on May 21, 2014. The museum, which was designed by the architectural firm DBB, assesses the implications and impact of 9/11.
The museum is entered through a glass pavilion created by Snøhetta, an international design firm best known for its design of the opera house in Oslo, Norway.
Multimedia displays and artifacts from the Twin Towers spread around 110,000 sq. ft. (10,000 sq.m.) of exhibition space tell the story of the attack and its impact.
One of the many trees planted at the memorial site is known as the 'Survival Tree'. The tree, a Callery pear, was recovered from the rubble of the
WTC in October 2001. Originally planted in the 1970s, the tree was badly damaged and burned but still had a living branch. It was nursed by the N.Y.C. Parks Department and recovered. In December 2010 the tree was replanted at the memorial plaza.
Despite initial claims that the memorial grounds would not be isolated and would be integrated into the fabric of Manhattan, the site is now cordoned off and you need a pass to access the site. Passes can be purchased at the official
site of the 9/11 Memorial.