On the grounds of ONS Recreatieoord is a special bunker located, that consists of two bunkers that are built together. The front part is a defense bunker, Type S7 ‘Porcupine bunker’ with loopholes. In 1943 the Germans added another part, which is a type VF2B crew shelter for 6 men. The bunker has been neglected for a long time and is currently being renovated.