The Black Tower (Černá věž) is a 16th-century belfry that stands just off the main square, connected to the Cathedral of St Nicholas by a covered passage. Its dark exterior — the tower was given a black tar coating after fire damage — contrasts with the lighter buildings around it. The climb up the 225 steps is steep but worth it: from the top there are clear views across the old town rooftops and out to the Šumava hills on the southern horizon.
The tower's four bronze bells include the largest bell in the South Bohemian Region. The belfry is open to visitors and the view from the top makes it the single best vantage point in the city. Count on about ten minutes of determined climbing each way.