The World Trade Center officially opened on April 4, 1973. Here are photographs of the lower Manhattan buildings prior to the 9/11 terror attacks in 2001.
A helicopter flies past the Twin Towers of the World Trade Center in this undated file photo.
The Twin Towers of New York's World Trade Center rise over the World Financial Center. (June 23, 1999)
Philippe Petit, a French high wire artist, walks across a tightrope suspended between the World Trade Center's Twin Towers. (Aug. 7, 1974)
An undated photo of the World Trade Center.
An undated photo of the World Trade Center, taken from Battery City Park.
Dawn breaks over the World Trade Center on the morning of March 1, 1993 as seen from Jersey City, N.J.
The New York City skyline. (July 20, 2001)
The Twin Towers of the World Trade Center. (Feb. 25, 1997)
Joe Constantino's "World Trade Center," 2009, from a 1996 negative, is part of Heckscher Museum of Arts "New York, New York" exhibit in Huntington through Oct. 16. 2011.