3. Old Croton Aqueduct Gatehouses
The Croton Aqueduct gatehouses provided access to the aqueduct for maintenance and regulation of water flow. There are three gatehouses on the Upper West Side along Amsterdam Avenue at 113th, 119th, and 135th Streets. The one above is just by Columbia University on 119th Street, the ones below at 113th and 135th Street, at City College:
