Quick answer
One World Trade Center is the 1,776-foot centerpiece of the rebuilt World Trade Center, the tallest building in the United States and the Western Hemisphere. It opened in 2014, and beside it the 9/11 Memorial marks the twin towers' footprints with two reflecting pools and the names of the 2,983 people killed in the 2001 and 1993 attacks.
Full transcript
The tower that fills the void
One World Trade Center rises from the northwest corner of the 16-acre World Trade Center site, on the ground where the original 6 World Trade Center stood. Designed by David Childs of Skidmore, Owings & Merrill, construction began in 2006 and the tower opened on November 3, 2014. It stands 1,776 feet — the year of the Declaration of Independence — making it the tallest building in the United States and the Western Hemisphere. The square base is 200 feet per side, the exact footprint of the old twin towers, and the roof reaches 1,368 feet, the same height as the North Tower that once stood there.
The pools
Beside the tower, the 9/11 Memorial opened on September 11, 2011, exactly ten years after the attacks. The design, called Reflecting Absence by Michael Arad and Peter Walker, was chosen in January 2004 from 5,201 entries from 63 countries. Two pools, each nearly an acre, sit in the footprints of the North and South Towers, with the largest manmade waterfalls in North America pouring 30 feet into their centers. Around them, bronze parapets carry the names of the 2,983 people killed in 2001 and 1993. Some 400 swamp white oaks shade the plaza, including the Survivor Tree, a pear tree rescued from the rubble in 2001 and returned in 2010.
Up, then down
The museum, which opened in May 2014, tells the story underground; the observatory tells it from above. One World Observatory on floors 100-102 opened on May 29, 2015, and its elevator climbs 102 floors in 47 seconds. Go up in late afternoon, when the light is best, then ride down and walk the pools slowly at dusk. Stand by the water and read a few names; the sound of the falls covers the city noise, and you will understand why the memorial is the reason the tower exists.