[](http://www.pc.gc.ca/eng/lhn-nhs/on/trentsevern/visit/visit6/lock21.aspx) The Peterborough Lift Lock is a boat lift located on the Trent Canal, and is Lock 21 on the Trent-Severn Waterway. The project included many technical and engineering firsts. It was the first to be built from concrete, and was the highest (19.8 m) boat lift in the world to be built out of unreinforced concrete (This was a considerable accomplishment at the time when conventional locks usually only had a 2 m rise). The Peterborough Lift Lock was named an Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers in 1987.