Yesterday I learned about Bruniquel Cave in France.

Neanderthals broke off stalagmites and stalactites and used them to create a structure in a cave almost 200,000 years ago.

https://en.m.wikipedia.org/wiki/Bruniquel_Cave

“The artificial ring structures made of broken stalagmites now have been dated by uranium series dating as 176.5 (±2.1) thousand years old, with 2σ uncertainties (95.5% probability). There are two annular structures, one 6.7 by 4.5 metres (ellipse major/minor axes), and the other 2.2 by 2.1 metres (ellipse major/minor axes), composed of one to four aligned layers of stalagmites, with some small pieces placed inside the layers to support them. Some stalagmites were placed vertically against the rings, possibly as reinforcement. There are also four stacks of stalagmites measuring between 0.55 and 2.60 metres in diameter, two of which were inside the large ring and two outside it. Approximately 400 stalagmite pieces (called “speleofacts” by the researchers) were used in the construction of the structure, with a total length of 112.4 metres and weight of approximately 2.2 tons.”

That means these fossilized sea creatures were most likely collectibles, deliberately gathered by the ancient hominins for some purpose besides essential utility.

Funko Pop strikes again. Poor caveman Grog never was able to track down that ultra rare ammonite to complete his collection