It is difficult to imagine what happened here almost 13,000 years ago: In the midst of gently rolling hills the roof was suddenly blown off a magma chamber which had formed beneath the Earth's surface. The whole area was shaken by a huge explosion, which was caused by hot gases coming into contact with groundwater. The volcano ejected vast quantities of ash and pumice.
After only a few days the conduit was so big that a gigantic column of ash rose 30 kilometres into the sky. The wind carried volcanic particles more than 1,000 kilometres to the north-east - as far as southern Sweden. And to the south, volcanic dust rained down as far as northern Italy.
The immediate surrounding area was buried under a heavy load of stone more than 50 metres thick. And currents of hot gases and rock fragments raced down the nearby valleys, leaving them filled with masses of volcanic rock. The spectacle went on for about two weeks and left a basin measuring two kilometres by three kilometres. We are now standing on the edge of the basin.
Rain washed the fine-grained particles down from the slopes to create an impermeable layer of mud at the bottom of the basin. And so the Laacher See (Lake Laach) was formed. It is 51 metres deep at its deepest point, which lies directly over the vent.