Havet is part sauna, part waterfront meeting place, and part cultural venue, giving Trondheim a contemporary version of the Nordic harbour hangout. Depending on the programme, you might find concerts, food, cold plunges, sauna sessions or a crowd simply using the water's edge as a social space.
It is not a historic sight, but it says something useful about the city now: practical, outdoorsy and increasingly comfortable turning former harbour edges into public life. Book ahead for sauna sessions when demand is high.