The castle and its tower — Český Krumlov Castle is the town's crown — a sprawling complex on the ridge, second in size only to Prague's, with courtyards of sgraffito and painted decoration, the distinctive round tower banded in painted "stonework," a beautifully preserved Baroque theatre (one of the rarest survivals of its kind, shown on special tours), the multi-level covered Cloak Bridge, and a moat that keeps bears. Climb the tower for the definitive view over the red roofs and the river loop, tour the interiors, and don't miss the terraced gardens above. It's the essential half-day.
The red-roofed maze — The old town, wrapped almost entirely by the Vltava, is a joy to wander — a dense, steep tangle of cobbled lanes and Renaissance and Baroque houses in ochre and pastel, opening onto the main square with its town hall and plague column, and the tall church of St Vitus. There's no single sight beyond the castle so much as the whole picture-perfect town; get lost in the lanes, cross the bridges, and photograph the roofs and the river. It's magical in the early morning and evening, once the coaches have gone.
The Vltava and rafting — The river is central to Český Krumlov's charm and its fun — it loops right around the town, with weirs, bridges and riverside beer gardens, and it's a favourite for rafting and canoeing. You can paddle a stretch of the gentle Vltava down to or through the town (a popular, easy adventure), or simply take a riverside table and watch the rafts drift by. The green water and the castle reflections are part of what makes the place, and getting on the river is a lovely counterpoint to the lanes.
Art, festivals and Bohemian flavours — Český Krumlov has a cultural streak — the Egon Schiele Art Centrum honours the painter who worked here, and the summer brings festivals, above all the Five-Petalled Rose Renaissance festival, when the town dresses in costume. The food is hearty Czech-Bohemian — roast pork and dumplings, goulash, svíčková, trdelník and superb beer (South Bohemia is beer country, home to Budweiser Budvar). Between the castle and the river, take in an art show or a festival, and settle into a beer garden for the local brew.