Penascosa is one of the most visited rock-art areas in the Côa Valley, partly because access is easier and partly because the setting is beautiful in a dry, open way. The engravings include Paleolithic animals cut into schist panels near the river.
Tours usually leave from Castelo Melhor rather than the main museum, so check the departure point when booking. It is the right choice if you want a clear, manageable introduction to the valley sites.