Muscat grapes, and specifically raisins, were once the main source of wealth in this area.
Grapes were laid out to dry in these Riuraus on wattle beds which were shielded from humidity and rain. The Riuraus in question are porches with semicircular arches, many of which were located in front of houses, though some of them were free-standing or attached to the side of a building. You can only look at them from the trail without invading private property.