When this photo of One World Trade Center was taken in mid-2013, it had just become the tallest skyscraper in America at 1,776 feet. This height is a tribute to the U.S. Declaration of Independence and to the 2,600 people who died at Ground Zero on 9/11. After years of construction delays, the Freedom Tower opened at the end of 2014. The final cost was about $3.9 billion.