In the eastern Eifel, volcanism began about 500,000 years ago in the area of today's Laacher See; it extended to the Neuwied Basin to the south, and crossed the Rhine to the east. The quantity of basalt lavas, pumice tuffs and ash tuffs produced by the volcanoes was far greater here than in the western Eifel. East Eifel volcanism came to an end with a huge eruption, as a result of which the magma chamber emptied and collapsed, creating a caldera. Today's Laacher See formed in the caldera. The ashes from the eruption can be detected today in deposits all over Central Europe and as far as Bornholm as a thin layer.