Stockholm City Hall (Stockholms stadshus) is an early 20th-century National Romantic masterpiece by architect Ragnar Östberg, completed in 1923. The square red brick tower — 106 metres tall and topped with three golden crowns — has become the symbol of the city. The building sits at the water's edge where Lake Mälaren meets the Baltic, and the view from the tower on a clear day is one of the best in Stockholm.
The interior is equally impressive: the Blue Hall hosts the annual Nobel Prize banquet (for 1,300 guests), while the Golden Hall upstairs has 18 million gold mosaic tiles depicting figures from Swedish history. Tours are the only way to see the interior, and access to the tower is by guided tour too (limited numbers, first-come basis).