Prehistoric People Built Mysterious Structures Inside a Spanish Cave

Spain keeps generating new surprises all the time!

In a cave called Cova Dones, located in Millares, Spain, scientists have found something incredible: over 100 stone structures built by prehistoric humans more than 20,000 years ago. These structures, called speleofacts, were made by breaking, moving, and stacking pieces of stalagmites (the cone-shaped rocks that grow up from cave floors).

Archaeologists say this is one of the most important underground discoveries ever made—second only to a cave in France.

Cova Dones, located in Millares, Spain

The people who built these formations didn’t do it randomly. Experts believe the shapes and patterns of the rocks show that ancient people carefully planned how to use the space inside the cave. They may have created these formations for rituals, to mark territory, or to organize the cave into different areas.

The researchers were able to figure out how old the formations are by studying the calcium that formed over the broken rocks. This helped prove that the structures really were made in prehistoric times. Scientists plan to keep studying the site to learn more about when exactly the structures were built and why.

This isn’t the first big discovery from Cova Dones. In 2023, researchers found over 100 pieces of cave art there—including drawings and carvings of animals like horses, deer, and ancient cattle called aurochs. These artworks are about 24,000 years old and were made deep inside the cave, but still in places people could easily walk to.

Not long after that, scientists also found a Roman sanctuary in the cave that’s about 1,900 years old. It had Roman writings and even a coin from Emperor Claudius’s time. There’s still a lot of the cave left to explore, so more amazing discoveries may be waiting inside.