When workers in the Wartgesberg quarry were doing some blasting in 1969, they were more than a little amazed! A round boulder measuring 5 metres in diameter fell out of the middle of the wall of the quarry. A lava bomb? Even experts were uncertain to start with, because it is difficult to imagine that the Eifel’s volcanic forces were powerful enough to throw 120 tons into the air.

Drilling into the centre of the 'lava bomb' clarified what had happened: During the eruption of the Wartgesberg Volcano, part of the crater wall came loose and a boulder rolled down the wall into the conduit. Just like a snowball which becomes bigger and bigger as it rolls down a slope, the piece of rock rolled through magma, which stuck to its surface.

During the next eruption, the ball-shaped rock was thrown up and then rolled back down again. This happened again several times until the rock became buried inside the crater and eventually reappeared thousands of years later.

Our tip: Under the motto 'Experiment with it! Touch it! Try it out!', the Vulkanhaus Strohn (Strohn Volcano House) presents an exciting interactive exhibition for everyone who is enthusiastic about the fascinating world of volcanoes.