Stockholm is built across fourteen islands, and we decided early to let the water set our route. The ferries are part of the city's transit, which means you can drift between neighborhoods for the price of a bus ticket, the summer light stretching the evening out for hours.
We toured the old town in the morning, lost an entire afternoon to the museums, and ended each day on a boat going nowhere in particular. We came home calmer than we left, which is, I think, the highest thing I can say about a trip.