Explore Hesse Frankfurt am Main Darmstadt and around Wiesbaden The Taunus Along the River Lahn Marburg Fulda and around Fritzlar and around Kassel Share A few kilometres east of Darmstadt is the GRUBE MESSEL, a redundant oil-shale pit on the site of an ancient volcanic crater-lake which has yielded such rich fossil finds that it is now a UNESCO World Heritage Site. The fossils date from the Eocene period around 49 million years ago, when the climate in what is now Hesse was subtropical; the present-day descendants of many of the species found here – including opossum, anteaters, flightless birds and crocodiles – are now only found far from Germany. The fossils are in exceptionally good condition, often preserving food residue in their stomachs: the macrocranion – a relative of the modern hedgehog – has been found with fish bones in its stomach, while the stomachs of the world’s oldest-known bats preserve the scales of moths and butterflies. One theory for the unusual richness of the finds is that poisonous gas from the crater-lake – a so-called maar volcano – killed the bats. Messel is particularly famous for its fossils of ancient horses, which were tiny compared with their modern descendants. The impressive new Besucherzentrum (visitor centre) has displays relating to the origins and history of the site, from vulcanicity and the evolution of the landscape to its later industrial heritage. Between April and October it organizes regular daily guided tours of the pit itself; it’s advisable to book in advance, since demand is heavy. The centre has a café. There’s also a small museum, the Fossilien und Heimatmusem Messel, in the old centre of Messel north of the train station, with lots of fossils on display; it’s worth visiting this and the Senckenberg Museum in Frankfurt as well as seeing the pit.