In Prats is located the sanctuary of "Roc de les Bruixes", a set of rock-engraved ritual themes dating from the Bronze Age and the Iberian era, to the Early Middle Ages. Originally it was a sacred place from where the Iberians extracted stone powder to make ointments. Late Gothic remains such as the necropolis of Sant Joan de Caselles or the one aside Sant Serni de Canillo in the late 7th and 8th century provide proof of the early Christianity in Andorra.