Oosterleek with the Zuiderdijk part of the Westfriese Omringdijk. This is a 126km long (former) sea dike that consists of several linked shorter dikes. Its origins date back to the 13th century; in the 16th century the West Frisian Circular Dike was given its present form and served as a sea dike until the construction of the Afsluitdijk..© 28 juni 2019 Aerophoto-Schiphol Aerial Photography