Forges du Saint-Maurice is the strongest excursion from Trois-Rivières. The site preserves the remains of the ironworks that operated here from the 18th century and helped start Canada's iron and steel industry.
The setting beside the Saint-Maurice River is open and green, with ruins, exhibits, and interpretation that make the industrial story readable even if you are not usually drawn to machinery. It is seasonal, so check Parks Canada hours before going.