or Laach Lake (in English) is a volcanic caldera lake with a diameter of in Rhineland-Palatinate, Germany, about northwest of Koblenz and south of Bonn, and is closest to the town of Andernach situated to the east on the river Rhine. It is in the Eifel mountain range, and is part of the East Eifel volcanic field within the larger Vulkaneifel. The lake was formed by a Plinian eruption approximately 12,900 years ago with a Volcanic Explosivity Index (VEI) of 6, on the same scale as the Pinatubo eruption of 1991.