I just stumbled upon a documentary, released only 2 months ago, called Neandertal, the Mystery of the Bruniquel Cave. It's about the discovery and investigation of a Neanderthal circular 'structure' made entirely of stalagmites found inside a cave in France, which was explored for the first time in the 1990's.
According to wiki, the evidence points to the structure being about 176,000 years ago. Its complexity and its depth within the cave - which would have necessitated the use of fire for illumination - is apparently a first and points to Neanderthals being much more complex socially and perhaps possessing a more sophisticated intelligence than once assumed.
I been there! Not the cave, you're not allowed, just the exhibition in Bruniquel castle. But I'd be suspicious about their claim that they were neanderthals. We're talking standard 'out of Africa' stuff here.