Here's a look at the rebuilding of Ground Zero in lower Manhattan and the memorial to the victims of the September 11 attacks.
September 11 Memorial:
The memorial honors those killed on September 11, 2001 in all locations of the attack, as well as those killed on February 26, 1993, when terrorists set off a truck bomb in the basement of the World Trade Center.
Building planning and construction
Business and industry sectors
Government and public administration
Government bodies and offices
International relations and national security
New York (State)
New York City
Northeastern United States
One World Trade Center
Terrorism and counter-terrorism
Unrest, conflicts and war
Business, economy and trade
Destinations and attractions
Monuments and historical sites
National September 11 Memorial and Museum
Buildings and structures
Continents and regions
Points of interest
April 28, 2003 - The World Trade Center Site Memorial Competition launches.
June 2003 - The Memorial Competition submission period closes. 5,201 submissions are received from 63 nations.
November 19, 2003 - Eight prospective plans chosen from the submissions are displayed for the public in the World Financial Center in New York.
January 6, 2004 - The Lower Manhattan Development Corporation announces its choice of "Reflecting Absence" by Israeli-born architect Michael Arad.
September 10, 2005 - Supporters of the Take Back the Memorial campaign protest the inclusion of an International Freedom Center in plans for the memorial.
September 28, 2005 - In a written statement, Governor George Pataki announces that plans for the International Freedom Center adjacent to the planned memorial at the World Trade Center site have been abandoned.
July 12, 2011 - More than 42,000 passes to the memorial are reserved in the first 24 hours they are made available.
September 11, 2011 - The 10th anniversary of the 9/11 attacks and the dedication of the memorial.
September 12, 2011 - The memorial opens to the public.
2012 - A dispute between the Port of Authority of New York and New Jersey delays construction of the 9/11 museum planned for the memorial site. The museum was originally supposed to open on the 11th anniversary of 9/11.
September 10, 2012 - The budgetary dispute delaying the opening of the museum is resolved when all parties enter into a "memorandum of understanding," an agreement that allows them to restart construction.
May 15, 2014 - The National September 11 Memorial & Museum opens its doors for the 9/11 community -- survivors, families and rescuers. Within it are 12,500 objects, 1,995 oral histories and 580 hours of film and video.
May 21, 2014 - The museum opens to the public.
Redevelopment of Lower Manhattan:
Fall 2001 - New York Governor George Pataki and New York City Mayor Rudy Giuliani create the Lower Manhattan Development Corporation (LMDC). The mission of the LMDC is to "help plan and coordinate the rebuilding and revitalization of Lower Manhattan."
The LMDC also administers the World Trade Center Site Memorial Competition, a separate process from that of rebuilding the World Trade Center area.
A 15-member board of directors governs the LMDC. The governor of New York and the mayor of New York City each appoint half of the members. The LMDC is also assisted by nine advisory councils.
According to an audit conducted by the Port Authority of New York and New Jersey, the rebuilding cost grew from approximately $11 billion in 2008 to $14.8 billion in 2012.
August 12, 2002 - FEMA and the Federal Transit Administration announce $4.55 billion in federal aid for transportation improvements in Lower Manhattan.
September 26, 2002 - Six design teams are hired, out of 407 submissions, to create land use plans for the 16-acre site.
December 18, 2002 - An exhibit of nine possible designs opens at the World Financial Center.
February 27, 2003 - Daniel Libeskind's "Memory Foundations" is selected as the new design for the site.
September 17, 2003 - The LMDC releases a revised Master Plan for the site.
November 23 2003 - PATH train service is restored, linking Lower Manhattan and New Jersey. Trains operate out of a temporary station in the area.
December 19, 2003 - Plans for the Freedom Tower to be built at Ground Zero are revealed.
January 22, 2004 - Architect Santiago Calatrava unveils his plans for the area transportation hub.
July 4, 2004 - Construction at Freedom Tower begins. A 20-ton slab of granite, inscribed "the enduring spirit of freedom," is laid as the cornerstone of one of the new skyscrapers that will stand on the site.
May 4, 2005 - Governor Pataki calls for a redesign of the new tower for safety reasons.
June 29, 2005 - New York officials release the latest design for the signature building at the site after revising it to make the tower more secure.
September 6, 2005 - Architect Santiago Calatrava and public officials dedicate the first steel rail for the future transportation station.
December 15, 2005 - Architect Lord Norman Foster agrees to design the next major building planned for the site. Foster will design a 65-story tower for the northeast corner of the 16-acre site.
April 26, 2006 - The Port Authority of New York and New Jersey and developer Larry Silverstein reach an agreement about the financing of Freedom Tower, resolving problems that had delayed construction.
April 27, 2006 - The formal groundbreaking of Freedom Tower takes place.
March 26, 2009 - The Port Authority of New York and New Jersey announces dropping the name "Freedom Tower," and that the first commercial lease in the building has been signed. Upon completion, the building will be named One World Trade Center.
May 10, 2013 - Construction workers bolt the last pieces of a 408-foot spire into place atop One World Trade Center, bringing the building to a height of 1,776 feet. This height references the year the United States declared its independence. It also makes the building the tallest in the Western Hemisphere and the third tallest in the world.
November 3, 2014 - One World Trade Center opens for business, when the first tenant, Conde Nast, moves in.
May 29, 2015 - The observatory opens in the top three floors of One World Trade Center.
March 3, 2016 - The first phase of the World Trade Center transportation hub opens.
June 29, 2016 - Liberty Park opens to the public.