It turns out they built ornate homes out of bone. This from Richard Gray of The Telegraph:
Archaeologists have discovered the remains of a 44,000 year old Neanderthal building that was constructed using the bones from mammoths. The circular building, which was up to 26 feet across at its widest point, is believed to be earliest example of domestic dwelling built from bone. Neanderthals, which died out around 30,000 years ago, were initially thought to have been relatively primitive nomads that lived in natural caves for shelter.
The new findings, however, suggest these ancient human ancestors had settled in areas to the degree that they built structures where they lived for extended periods of time. Analysis by researchers from the Muséum National d’Histories Naturelle in Paris also found that many of the bones had been decorated with carvings and ochre pigments…
[Continues at The Telegraph]