You can watch it's five-year construction in two minutes.
From the Sept. 10, 2015, Yahoo! News by Billie Cohen.
This opened September 10, 2015, yesterday, one day ahead of its 14th anniversary.
It overlooks the crash site of United Flight 93 where the passengers stormed the cockpit and caused the terrorists to be unable to finish their mission which was most likely to crash into the White House or Capitol.
It crashed near Shanksville, Pennsylvania, and everyone on board died.