"Conjure up a vision of a central European river paradise with water clean enough to drink, banks lined with old-growth trees and swans gliding through rustling reeds. Amazingly you can find this just seven subway stops from Vienna’s city centre. As the Alte Danube (Old Danube – a former arm of the great river, now more like a lake) gently curves around Donaustadt’s skyscrapers, it offers nearly 8km of watery respite for an estimated one million visitors every year. Well-kept public swimming areas, boat-rental outfits, a sailing school, waterfront restaurants and private cabanas line the shore. “When the weather’s good we come here,” says media consultant Ralf Strobl, who’s known to sleep in his cabana in a marina near the U1 stop. To really experience life like a Viennese, this is a must-visit."