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.

Credit: AP

A helicopter flies past the Twin Towers of the World Trade Center in this undated file photo.

Credit: AP

The Twin Towers of New York's World Trade Center rise over the World Financial Center. (June 23, 1999)

Credit: AP

The catamaran PlayStation sails past the Twin Towers of the World Trade Center in New York Harbor. (Oct. 7, 1999)

Credit: AP

Philippe Petit, a French high wire artist, walks across a tightrope suspended between the World Trade Center's Twin Towers. (Aug. 7, 1974)

Credit: Newsday / MICHAEL E. ACH

An undated photo of the World Trade Center.

Credit: Nathan L. Mangali

An undated photo of the World Trade Center, taken from Battery City Park.

Credit: Newsday / Ken Sawchuk

Dawn breaks over the World Trade Center on the morning of March 1, 1993 as seen from Jersey City, N.J.

Credit: AP

The Manhattan skyline and the Twin Towers of the World Trade Center are shown from Jersey City, N.J. (March 2000)

Credit: Bloomberg News/Jade-Snow Moy

The New York City skyline. (July 20, 2001)

Credit: AP

The Twin Towers of the World Trade Center. (Feb. 25, 1997)

Credit: Joe Constantino

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.

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