 The mall itself played an important role during the attacks because the people who were evacuating the Twin Towers could not exit outside onto the plaza because of falling debris, so they traveled through the mall, and exited through either 4 or 5 World Trade Center.Westfield World Trade Center has roughly of retail space.Although the new mall is only spread over roughly one-half of the original mall's footprint (due to the new space required for the below-grade National September 11 Memorial & Museum), the mall is double-level, whereas the original mall was a single level.