The Dwingeloo Radio Observatory (near Dwingeloo, m. Westerveld, in the northeastern Netherlands), is a single-dish radio telescope with a diameter of 25 m. Construction started in 1954, and the telescope was completed in 1956. At that time it was the largest radio telescope in the world. As of 2000, it was no longer in operation in an official capacity and since August 2009 is officially a Dutch industrial heritage monument.