Demolition crews bring down Houston skyscraper Jan 9 11:56 AM US/Eastern HOUSTON (AP) - It didn't take long - mere seconds, in fact - to create a new hole in the skyline of Houston's medical district. Demolition crews used high explosives to implode the 20-story former Prudential Building that had been a landmark of the district landscape southwest of downtown Houston since 1952. The crews had planned initially to touch off the explosives shortly before 8 a.m. Sunday, but dense fog delayed the series of blasts until 11:15 a.m. The Prudential Insurance Co. of America built the 500,000-square-foot skyscraper to serve as its southwest regional headquarters. The M.D. Anderson Cancer Center bought the building in 1974 and made it the center's main building in 1980 before vacating and closing the building in April 2010.