Fort Vijfhuizen is one of forty-two forts in the Defense Line of Amsterdam, a World Heritage Site. It is located in the town of Vijfhuizen on the ringvaart which surrounds the Haarlemmermeer polder. The main fort is currently maintained by a charitable foundation called Kunstfort Vijfhuizen which leases space for twelve artist studios and a restaurant. The fort is now a center for artistic experiment and a development site for scenarios for peaceful futures, focusing on the intersection of military heritage and ecology.