Built in 18th-century, the tiny artificial island called Wilhelmstein is located on Lake Steinhude, the largest lake in northwestern Germany. The island is based on piles of stones, that had to be carried there by the local fishermen in their boats. Between 1765 and 1767 it was turned into a military fortress by William, Count of Schaumburg-Lippe. His vision was an impenetrable getaway in his own land. In 1772, the first German submarine, Steinhuder Hecht, was constructed on the island. Wilhelmstein today is a museum and a popular tourist destination Steinhuder Meer. For more information please visit the official website.
Location: Lower Saxony, Germany.