In just a few weeks, I received two cards of the Messel Fossil Pit in Germany. The pit was dug as a quarry, then almost became a landfill before being declared a UNESCO site in 1995. The pit is important to scientific understanding, as it contains a great variety of exceptionally well-preserved mammals, birds, reptiles, insects, and plants. Not only are there complete skeletons of the animals, but in some cases even fur and feathers are preserved.
My first card of the Messel Pits came as an official Postcrossing card from Michael:
The second card comes from Svea, through a private swap:
This card shows more of the well preserved fossils that the site is known for.