From the World Heritage inscription:
The Messel Pit has provided a wealth of fossils that have greatly increased understanding of the Eocene Age. It is a small site approximately 1,000 m long (north to south) and 700 m wide (east to west).
The Eocene (‘dawn of new times’) epoch (57-36 million years ago) was a remarkable period in the evolution of life on Earth. This was the time when mammals became firmly established in all the principal land ecosystems. They also reinvaded the seas (e.g. whales) and took to the air (e.g. bats). During this period of geological time, North America, Europe and Asia were in continuous land contact and the partial explanation of current distribution patterns is provided by the Eocene fossil record.
The Messel Pit provides the single best site which contributes to the understanding of the middle part of this period. Messel is also exceptional in the quality of preservation, quantity and diversity of fossils. Messel offers fully articulated skeletons and the outline of the entire body as well as feathers, hairs and stomach contents.
Paleontology and archeology sites can be very hit or miss affairs as far as tourist attractions. They almost always represent some important discovery that furthered our understanding of the Earth’s history or of a civilization. The physical site however is also almost always nothing more than a hole in the ground…. and you usually can’t even see the hole because they have either ended the dig or it is off limits.
The fossil site at Messel is one of the better dig sites that I have visited. (also see Sangiran and Ban Chaing) The museum and interpretative center are top notch and do a great job explaining why the site is important and the major discoveries that have been found. They also go into the history of the site and how it was saved from becoming a dump.
Messel is located 30 minutes from Frankfurt and is one of the easiest World Heritage sites to visit if you are in the area. Unlike most dig sites, you can also view the actual fossil pit (where work is still being done in the summer) as well as go down into the pit on a guided tour.
The pit itself is quite small and is the location of a former lake. The reason why it is such a great site for fossils is that creatures were buried in the lake for hundreds of thousands of years and were preserved in layers of algae at the bottom. Perhaps the most significant find at Messel was that of Darwinius masillae, a very early proto-primate.
Selecting an image to display for a paleontology site is always difficult, but in the end I thought a fossil was more representative and interesting than a photo of a hole in the ground.
View my complete list of UNESCO World Heritage Sites.