This was a site that I really had no preparation for visiting and it was a split second decision at Darmstadt station that brought us here instead of Lorsch. What we didn't realise was that the fossil site is not open between November and April.
When the information centre is closed you will be able to go to the viewing platform to look across the pit (picture). There is some information here and a high tech telescope, which can give you an overview of the site. That is about all you can see in the winter, so really is not worth the effort of getting to.
Fortunately the information centre is staffed by a group of very friendly scientists, who came out and spoke to us. We described why we were there; mentioning this web site, and they invited us in. They put on a video in German explaining more about the history of the site, showed us some geological samples, gave us books and coffee, and at the end of our visit they even drove us back to the station; so Vielen Dank Susana and co.
Inside the Information centre is the UNESCO certificate, behind a model of the small horses found in the mine. There is also a model of the new Visitors Centre that will be built in the next few years; it looks like a very impressive piece of architecture.
Messel has a small railway station, no real platform though, on the Darmstadt - Aschaffenburg line. It takes about 40 minutes to get to Messel from Frankfurt so is fairly easy to visit. From the station it is about a 20-minute walk (there is no bus) out of town to the south. There is a small cycling sign pointing in the right direction and there is a path next to the road through the forest, and there is a large sign at the turn off from the road.
I really enjoyed my visit here, mostly for the fantastic welcome and hospitality shown to us by the staff here. We did manage to get a good idea of the importance of the site from them and managed to see the pit itself, so I feel that I can count this as a proper visit even if we didn't manage to get down into the site itself.