Manhattan, New York

Amtrak - "Freedom" Tunnel (New York County, New York)
Built in the 1930s
Tunnel on Railroad (Amtrak) under Riverside Park
Open to traffic

High Line Elevated Park (New York County, New York)
Built 1929-34; Abandoned in 1980; Faced threats of demolition in the mid-1980s and again during the Guliani administration; Conversion into a park began in 2006; Section I opened in 2009; Section II opened in 2011; Section III Opened 2014
Park built on steel stringer bridges over city streets
Open to pedestrians only

NYC - 69th Street Transfer Bridge (New York County, New York)
Built 1911
Abandoned pony/through plate girder bridge over Hudson River on railroad
Abandoned

West Side Elevated Highway - Canal Street Overpass (New York County, New York)
Built 1938, demolished 1981
Steel through arch bridge over Canal Street on West Side Elevated Highway
Demolished