The defensive structure was erected in 1936 as part of the New Dutch Seaside program. Then the chain of fortifications stretched for 81 km. Now almost all the bunkers are used by the inhabitants of the Netherlands for sports.
The bunker near Vreswijk (Utrecht province) has long stood abandoned on the edge of the polo field.
UN Studio architects have wrapped the concrete block with a metal shell, which is supported by a system of steel beams. A console with a wide panoramic window juts out to the side of the field, from where visitors of the cafe-tea can watch the game.
