10. The One World Trade Center Height : 1,776 ft (541.3 m) Floor count : 104 (+ 5 basement floors) Lifts / elevators : 73 Construction started: April 27th 2006 Opening : June 2013 Architect : David Childs Status : full tower structure and antenna  Its spire reaches a symbolic height of 1,776 feet (541 m) in reference to the year of the United States Declaration of IndependenceUnited States Declaration of Independence It has been nine years since terrorists targeted the Twin Towers of the World Trade Center, along with the Pentagon and White House in Washington, D.C. On September 11, 2001, terrorists managed to destroy the towers and damage the Pentagon. The plane believed to be aimed at the White House came down in a field in Pennsylvania. Since then, workers have been busy at the site, first clearing it, then preparing it for a new skyscraper and a memorial to the 2,792 people killed there : the One World Trade center