Six World Trade Center was first proposed in 1968 as part of the original World Trade Center complex . The building was designed by Emery Roth & Sons , along with Yamasaki Associates . Construction was completed in 1973 . The original Six World Trade Center was home to the U.S. Customs Service for the state of New York , from 1974 to 2001 . It was a 537,693-square-foot ( 49,953-square-meter ) , eight-story building , the shortest in the World Trade Center complex . From the Austin J. Tobin Plaza level , on which the main structure was built , it had a height of 92 feet ( 28 m ) but was 105 feet ( 32 m ) above the actual ground level . It was demolished following the destruction of the World Trade Center during the September 11 attacks , when 10 al-Qaeda participants hijacked American Airlines Flight 11 and United Airlines Flight 175 , crashing them into the Twin Towers . After burning for less than two hours , both 110-story towers collapsed . The collapse of the North Tower destroyed Six World Trade Center beyond repair , and the remnants of the building were pulled down using cables
September 11 attacks
September 11 attacks
Six World Trade Center