The mother of all ksour (castles) is the 16th-century fortified village at Tamnougalt, one of the oldest mud-brick ksar still standing and an essential stop on any Moroccan architecture pilgrimage. The maze of rooms leads through a sizable mellah, dips underground with strategically placed skylights and candle nooks, and emerges into dazzlingly bright courtyard stables lined with horseshoe arches. See if you can distinguish between the Arab, Andalusian and Berber Jewish motifs that blend so seamlessly here.