The destruction of  Minoru Yamasaki's Twin Towers caused unfathomable harm to New Yorkers. But that horrific day 12 years ago also left behind a physical void in the New York skyline, and the question became how to rebuild on that downtown land while also honoring the victims of the tragedy. A NOVA documentary airing tonight on PBS takes a look at the final construction stages of the 1,776-foot One World Trade Center by  Skidmore, Owings & Merrill as well as the National September 11 Museum. The documentary, " Ground Zero Supertower," follows up on the Emmy-nominated special " Engineering Ground Zero" that first aired in 2011.