The Welland Canals Centre at Lock 3 is the must-see of St. Catharines. The combined museum, viewing platform, and tourist office sit on the bank of the canal a few minutes north of downtown. The elevated deck looks straight down into the working lock, and several times a day a 225-metre lake freighter comes through carrying iron ore, grain, or coal between Lake Ontario and Lake Erie.
The St. Catharines Museum inside covers the history of the canal — there have been four successive canals along the same line since 1829 — and the city that grew up around it. A real-time AIS display tracks all ships in the canal so you can predict when the next vessel will arrive. Free admission to the platform; a small charge for the museum.