The towns of Noranda and Rouyn in Northwestern Quebec were once separated by a lake polluted by the waste products from the process of turning ore into copper. The owners of the mine and factory, mostly Anglophones, lived in Noranda, and the Francophone workers lived in Rouyn, where they had carefully built their public buildings so that their backs were to the lake. The two towns nevertheless united in astonishing harmony over the course of the 1980s. The two riverside communities realized, at about the same time, that the lake that separated them could become a bridge between them if they looked it as a common good, and then joined forces to purify it.