El museo en memoria a los atentados a las torres gemelas

An American flag found at the World Trade Center site (below) and a photograph of a flag raising at the site by Thomas E. Franklin/The Record (Bergen County, New Jersey) (top), seen during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. "MANDATORY MENTION OF THE ARTIST UPON PUBLICATION" AFP PHOTO/Stan HONDA

Remains of a New York City Fire Department Ladder Company 3 truck just outside the Historical Exhibition area during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

A New York Fire Department ambulance, is seen during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

NEW YORK, NY – MAY 14: The destroyed Ladder 3 fire truck is viewed during a tour of the National September 11 Memorial Museum on May 14, 2014 in New York City. The long awaited museum will open to the public on May 21 following a six-day dedication period for 9/11 families, survivors, first responders, workers, and local city residents. For the dedication period the doors to the museum will be open for 24-hours a day from May 15 through May 20. On Thursday President Barack Obama and the first lady will attend the dedication ceremony for the opening of the museum. While the construction of the museum has often been fraught with politics and controversy, the exhibitions and displays seek to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing while also educating the public on the September 11 attacks on the World Trade Center, the Pentagon and in Pennsylvania. Spencer Platt/Getty Images/AFP == FOR NEWSPAPERS, INTERNET, TELCOS & TELEVISION USE ONLY ==

Pieces of the plane of Flight 11 seen during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

A photograph of one of the World Trade Center towers collapsing after the September 11, 2001 attack, seen during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

NEW YORK, NY – MAY 14: A recovery mask used by a burn victim from the attacks on September 11 is viewed during a tour of the National September 11 Memorial Museum on May 14, 2014 in New York City. The long awaited museum will open to the public on May 21 following a six-day dedication period for 9/11 families, survivors, first responders, workers, and local city residents. For the dedication period the doors to the museum will be open for 24-hours a day from May 15 through May 20. On Thursday President Barack Obama and the first lady will attend the dedication ceremony for the opening of the museum. While the construction of the museum has often been fraught with politics and controversy, the exhibitions and displays seek to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing while also educating the public on the September 11 attacks on the World Trade Center, the Pentagon and in Pennsylvania. Spencer Platt/Getty Images/AFP == FOR NEWSPAPERS, INTERNET, TELCOS & TELEVISION USE ONLY ==

A display showing information, is seen during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

NEW YORK, NY – MAY 14: Cards, patches and mementos of those killed at Ground Zero are are viewed during a preview of the National September 11 Memorial Museum on May 14, 2014 in New York City. The long awaited museum will open to the public on May 21 following a six-day dedication period for 9/11 families, survivors, first responders, workers, and local city residents. For the dedication period the doors to the museum will be open for 24-hours a day from May 15 through May 20. On Thursday President Barack Obama and the first lady will attend the dedication ceremony for the opening of the museum. While the construction of the museum has often been fraught with politics and controversy, the exhibitions and displays seek to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing while also educating the public on the September 11 attacks on the World Trade Center, the Pentagon and in Pennsylvania. Spencer Platt/Getty Images/AFP == FOR NEWSPAPERS, INTERNET, TELCOS & TELEVISION USE ONLY ==

An American flag found at the World Trade Center site (below) and a photograph of a flag raising at the site by Thomas E. Franklin/The Record (Bergen County, New Jersey) (top), seen during a press preview of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. "MANDATORY MENTION OF THE ARTIST UPON PUBLICATION" AFP PHOTO/Stan HONDA

NEW YORK, NY – MAY 14: A salvaged section of steel facade from the North Tower from Ground Zero is viewed during a preview of the National September 11 Memorial Museum on May 14, 2014 in New York City. The long awaited museum will open to the public on May 21 following a six-day dedication period for 9/11 families, survivors, first responders, workers, and local city residents. For the dedication period the doors to the museum will be open for 24-hours a day from May 15 through May 20. On Thursday President Barack Obama and the first lady will attend the dedication ceremony for the opening of the museum. While the construction of the museum has often been fraught with politics and controversy, the exhibitions and displays seek to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing while also educating the public on the September 11 attacks on the World Trade Center, the Pentagon and in Pennsylvania. Spencer Platt/Getty Images/AFP == FOR NEWSPAPERS, INTERNET, TELCOS & TELEVISION USE ONLY ==

NEW YORK, NY – MAY 14: Surviving firefighter Dan Potter's fire helmet, which he used at Ground Zero on September 11, is viewed during a tour the National September 11 Memorial Museum on May 14, 2014 in New York City. The long awaited museum will open to the public on May 21 following a six-day dedication period for 9/11 families, survivors, first responders, workers, and local city residents. For the dedication period the doors to the museum will be open for 24-hours a day from May 15 through May 20. On Thursday President Barack Obama and the first lady will attend the dedication ceremony for the opening of the museum. While the construction of the museum has often been fraught with politics and controversy, the exhibitions and displays seek to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing while also educating the public on the September 11 attacks on the World Trade Center, the Pentagon and in Pennsylvania. Spencer Platt/Getty Images/AFP == FOR NEWSPAPERS, INTERNET, TELCOS & TELEVISION USE ONLY ==

NEW YORK, NY – MAY 14: Artifacts from Ground Zero are are viewed during a preview of the National September 11 Memorial Museum on May 14, 2014 in New York City. The long awaited museum will open to the public on May 21 following a six-day dedication period for 9/11 families, survivors, first responders, workers, and local city residents. For the dedication period the doors to the museum will be open for 24-hours a day from May 15 through May 20. On Thursday President Barack Obama and the first lady will attend the dedication ceremony for the opening of the museum. While the construction of the museum has often been fraught with politics and controversy, the exhibitions and displays seek to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing while also educating the public on the September 11 attacks on the World Trade Center, the Pentagon and in Pennsylvania. Spencer Platt/Getty Images/AFP == FOR NEWSPAPERS, INTERNET, TELCOS & TELEVISION USE ONLY ==

Workers prepare for the opening of the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

A model of the World Trade Center buildings, seen during a press preview in the National September 11 Memorial Museum at the World Trade Center site May 14, 2014 in New York. AFP PHOTO/Stan HONDA

Two tridents from the original World Trade Center loom inside the National September 11 Memorial Museum as the new One World Trade Center rises outside during the dedication ceremony at the National September 11 Memorial Museum in New York, May 15, 2014. US President Barack Obama inaugurates Thursday, a museum commemorating the September 11, 2001 terrorist attacks, the culmination of three years of delays, controversy and financial woes as he opens a memorial to an event that changed America. AFP PHOTO / Allan Tannenbaum/POOL

The last column of the final steel beam ceremonially removed from Ground Zero is seen at the dedication of the National September 11th Memorial Museum in New York, May 15, 2014. AFP PHOTO / TIMOTHY A. CLARY / POOL