Initially dismissed as a forgery, the first discovery of Palaeolithic cave art at Altamira was vindicated by 1895 when equally ancient paintings were discovered in other caves.
The antiquity of portable art had already long been accepted. Palaeolithic art took many forms and has been found on every continent (except America where there were probably no people at that time) and is particularly richly represented in Europe and Australia.
Most famous are the paintings and engravings in caves and rockshelters in France and northern Spain.
Various explanations have been offered for this art. Some may have been purely decorative, but for most a different explanation must be found.
Some early scholars drew an analogy with more recent hunting magic - but there are relatively few hunting scenes and the preferred prey species are rarely represented.
Links to human and animal fertility have also been made, and general religious connotations seem plausible, given the other evidence we have of the aesthetic and intellectual development of our recent Palaeolithic ancestors.
Another reasonable suggestion, given the inaccessibility of much of the art, is that it played a role in initiation ceremonies. Small footprints have been found with several groups of artwork in inner caves.
The range of species depicted, some of them quite rare in the areas where they are shown, may have been intended to give youngsters an educational introduction to the possibilities and hazards of their environment.
