Randeck Maar

 The Randeck Maar is probably the most important trace of the Swabian volcano. It is the largest crater in the Urach-Kirchheim volcanic area, measuring around 1.2 km in diameter. A maar lake was formed at the end of volcanic activity about 17 - 20 million years ago due to the water impermeability of basaltic tuff in the volcanic vent. Fossils of sub-tropical fauna and flora from the Tertiary Period have been found in the abundant lake deposits.