an eight-lobed circular structure that contains 88 stories of occupiable space and a pyramid-shaped pinnacle surmounted by a slender steel spire. Both rise to a height of 1,483 feet (451.9 metres), which includes 242 feet (73.6 metres) for pinnacle and spire. Each building is supported by 16 large columns around its perimeter, which, along with the rest of the frame, are made of high-strength, steel-reinforced concrete rather than of structural steel; the exterior sheathing consists of stainless steel and glass. A skybridge two stories tall links the two towers between the 41st and 42nd