Memmert is a small East Frisian island off the northern coast of Germany, with an area of 5.2 square kilometres. Memmert is uninhabited, with only one house on the island for wildlife-spotting purposes. Occasionally, some guests from the neighboring islands visit Memmert for recreation. Memmert is officially a wildlife protected area.
The island plays an important role in Erskine Childers's novel The Riddle of the Sands.
Wikipedia https://en.wikipedia.org/wiki/Memmert
Coordinates 53°38'20.667" N 6°53'2.825" E