See http://myolympus.org/folder.php?id=470

The rather romantic impression deceives. This hill, called Silberbuck, is a hazardous waste site that was filled with debris of bombs and other hazardous remainings of the postwar period. It will be hazardous for more than 100.000 years. Originally it was the place where a megalonamanic stadium had been started to be built and the waste was thrown into the excavation. Nature needed only 50 years to cover it - but it's only cover and the sewage is drained into a poisonous lake where many people died during - forbidden - bathing.