Here's how Manhattan's skyline has changed in the 25 years since the 9/11 attacks

The Tribute in Light was tested ahead of the 25th anniversary of 9/11.Adam Gray/Getty ImagesThis year marks the 25th anniversary of the 9/11 attacks.The World Trade Center site has become a memorial to the 2,977 lives lost.Photos show how New York City rebuilt Ground Zero.Each September, two large beams of light reach into the night sky above Manhattan's Financial District.The installation commemorates those who were killed on September 11, 2001.This Friday marks 25 years since that day, when te