The tower of Stockholm's City Hall rises 106 metres above Kungsholmen, topped by the Three Crowns — the heraldic symbol of Sweden. You can climb to the top by guided tour during summer months, and the views over Lake Mälaren, Gamla Stan, and the rooftops of the city are worth every step of the 365 stairs.
The City Hall itself is the venue for the Nobel Prize banquet, held each December in the Blue Hall (which is actually red brick, not blue — the painter changed his mind but the name stuck). Tower tours depart from the main entrance; check the schedule as they run at fixed times and sell out quickly in peak season.