A 29-year-old woman plunged 30ft to her death off an escalator at the World Trade Centre Oculus.
Police said she was apparently trying to retrieve a hat while on the escalator with her twin sister at about 5.30am on Saturday in the New York transit hub. She fell to the main concourse floor.
Port Authority police spokesman Joseph Pentangelo said the woman was taken to a hospital where she was pronounced dead. Police are investigating the incident. Her name has not been released.
The 3.9 billion dollar transportation hub was designed by architect Santiago Calatrava and provides connections between New Jersey's PATH trains and New York City's subways and contains a shopping mall. It is also a major tourist attraction.