Schwanenwerder (English: "Swan Ait") is an island in the locality of Nikolassee in southwestern Berlin, located in a wider stretch of the Havel river close to the eastern shore of the Großer Wannsee lake. The neighbourhood is known as an affluent residential area and was home to notable people such as Alexander Parvus, Joseph Goebbels, Gustav Fröhlich, Ernst Udet, and Axel Springer.
The river island, with an area of about 250,000 m2 (2,700,000 sq ft), was first mentioned as Der Sandtwerder ("sand ait") in 1704. Also called Cladower Sandwerder after the opposite village of Kladow, the island in the mid 19th century was a deserted place, overgrown with shrubs and a few trees. In 1882, the island was purchased by Wilhelm Wessel, a wealthy inventor and manufacturer of kerosene lamps, for a sum of 9000 marks. He ordered extensive landscaping, built an access ringroad, subdivided the area and offered the lots for sale. The intention was for wealthy buyers like himself to build cottages with access to the river. He himself had a mansion, called Villa Schwanenhof (Swan Court), erected in the centre of the isle. Its continued existence makes it the oldest building on the island. For convenient access, a small bridge was built which up to today remains the only way onto the island.
In 1896, a charter was drafted that banned inhabitants from setting up disturbing venues like factories and shops. Even a pier for river steamers was inhibited. In 1901, Emperor Wilhelm II granted the official use of the name Schwanenwerder, a more illustrious name than the old "Sand Ait". By then, only three villas had been erected, nevertheless the mansion colony quickly developed as a refuge of the wealthy Berlin bourgeoisie, among them Berthold Israel and Rudolph Karstadt, both owners of large department stores, the entrepreneur Leo Maximilian Baginski, and the banker Oscar Schlitter. Schwanenwerder was the most expensive property to purchase in the interwar German version of the Monopoly game.