Neanderthal: The Mystery of the Bruniquel Cave

Discovered in 1990 in the Aveyron Gorges, near the village of Bruniquel, Bruno Kowalczewski discovers a cave which shows evidence of being inhabited by Neanderthals as far back as 47,000 years ago, with stalagmites arranged in circles. What significance do these limestone rings have? From when exactly do they date? For