what was on top of the twin towers
World Trade Center (1973–2001) Hat trusses (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building.[42] Only 1Â WTC (north tower) actually had an antenna fitted; it was added in 1978.[45] The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower.[42]