On Muggleberge, a mountain in the southeast of Berlin, construction work began in 1954 on a television tower that stood roughly 430 feet tall. The tower included an observation deck at a height of 230 feet. During the planning stage, though, someone forgot that, if complete, the television tower as planned would interfere with air traffic at Berlin-Schoenefeld, the most important airport in the region.
On December 13, 1955, construction work on the tower was stopped and the incomplete stump was turned into a post for the secret service of the former GDR. The reason for the stop in construction, and for the use of the stump, remained a secret for decades. It was said that the tower was intended to be used as a meteorological observatory, but construction was halted when it was determined that there was no requirement for such an object.
After the German reunification, the television tower was transformed into a radio relay station. The tower remains under lockdown and cannot normally be visited; it is not to be confused with the Muggelberge Observation Tower, which sits about .6 miles away.