Randecker Maar
The Randecker Maar is a maar – a volcanic crater about wide. It is in the alps of the Swabian Jura near Stuttgart and was formed around 17 million years ago. A lake formed in the crater and its bed is now a layer of the early Miocene in which many fossils have been found. Nowadays, the crater is drained by the Zipfelbach brook and so there is no longer a lake. The northeastern wall of the crater has eroded and opens to lower ground. This forms a natural pass for the seasonal migration of birds and insects as  they fly up and over the alps. This makes it a good point for observing these creatures and so an observatory was established there in 1969 by ornithologist – "Forschungsstation Randecker Maar e.V.". The maar and gorge of the Zipfelbach were designated as a nature reserve by local ordinances in 1971 and 1990 to preserve the landscape and its fauna and flora for science and popular enjoyment. The area conserved is now .