Hel, Poland

Hel Peninsula (Polish: Mierzeja Helska) is a 35-km-long sand bar peninsula in northern Poland separating the Bay of Puck from the open Baltic Sea. The width of the peninsula varies from approximately 300 m near Jurata, through 100 m in the most narrow part to over 3 km at the tip. Since the peninsula was formed entirely of sand, it is frequently turned into an island by winter storms. Until the 17th century the peninsula was a chain of islands that formed a strip of land only during the summer.