Cave paintings in the impressive and vast Nerja Caves near Malaga, Spain. Photo by Fundación Cueva de Nerja.
Articles from 2012 in the Daily Mail and New Scientist, among numerous other places, suggest that these could be as much as 42,000 years old and would be the only known artistic images created by Neanderthal man.
Archaeonerd thinks otherwise. In any case (I don’t know wether since 2012 the suggested dates were confirmed), they are probably very old.