Donau Insel (German for Danube Island) is a skinny 13-mile long island that bisects the Danube River, skirting along Viennas shore. The island was originally conceived in the 19th century to provide protection against flooding, an ongoing problem for many towns along the river. In 1970, the island received a major upgrade: a freshly-dug trench created the New Danube slice and the earthy guts were used to build up the island. In addition to functioning as a water diversion system, the island now boasts an active recreational life featuring bars, restaurants, bike paths, docks for boating, beaches (two of which are FKK, short for Freikorperkultur, the German phrase for Free Body Culture, aka nude), radio stations, a sports stadium, a waterpark, a climbing park, and lots and lots of green space. More Info below.