To anyone who grown up playing Age of Empires III, Lac-Saint-Jean would be familiar to them as being the giant body of water in the Saguenay map. Tactically speaking, it was one of the more tactically sound maps because there were only two routes for land attack around the lake.

Lookout to Lac-Saint-Jean 
Plage le Rigolet 
Véloroute des Bluets 
La Maison des Bâtisseurs
In real life, there’s a lot more land around the lake so it’s not really an obstacle, it’s more of a feature. The Véloroute des Bluets, or roughly the Cycling Trail of Blueberries, circumnavigates the lake and provides two-way bike lanes on most segments except the section that requires a bicycle ferry crossing and dismounting when crossing the narrow dams.

Dam 
Dam 
Dam 
View from a dam
There are a couple of lookout points as well as beaches like the Plage de Rigolet to enjoy the water, but the public washrooms close as early as August 31st at the end of the summer season.

Véloroute des Bluets 
View from a dam
La Maison des Bâtisseurs acts as kind of a community hall in Alma, on the western shore of the lake. It has a visitor’s centre, a museum-like permanent and temporary exhibitions, a shop selling local products, a library with genealogy services, and school and family programs.