According to researchers, hundreds of stalagmites, the mineral deposits which rise from the floors of caves, were used to make these structures. The dating techniques were used by the researchers to find out that these rings were broken off 175,000 years ago. The findings are reported in the journal Nature.
The round structures were found in Bruniquel Cave in South-West France. The stalagmites had been cut to similar lengths and laid out in two oval patterns up to 40cm (16in) high.
"Their presence at 336m from the entrance of the cave indicates that humans from this period had already mastered the underground environment, which can be considered a major step in human modernity," the researchers write in their study.
Co-author Jacques Jaubert, from the University of Bordeaux, said it is not possible that these rings could have come about by chance or have been assembled by animals.
Prof Chris Stringer, of London's Natural History Museum, called the discovery "remarkable", adding: "At around 175,000 years, these must have been made by early Neanderthals, the only known human inhabitants of Europe at this time. If there is still-buried debris from occupation, it would help us to determine whether this was a functional refuge or shelter, perhaps roofed using wood and skins, or something which had more symbolic or ritual significance. Some of the burning must surely be associated with lighting in such a dark location, but only further discoveries from this or other sites will show us how common were such deep cave occupations in the ancient past, and what their purpose might have been."