City Hall is the New York City Subway station known for its abandoned lower-level platform arrangement beneath the active platform area.
The historic City Hall station was built with a loop track so trains could reverse direction in a tight space beneath City Hall Park. Its curved platform and elaborate architecture made it an important early station, but the geometry could not safely accommodate newer, longer subway cars.
The station closed to passengers in 1945, although trains continue to pass through the loop. The closed station is often described as an abandoned station, but it remains part of the operating railroad and can be seen from a downtown 6 train.
South Ferry also has a complicated history, including an older loop station and a newer terminal. That similarity makes it an easy alternative, but the famous surviving ornate loop station is City Hall.