Although you could visit Palermo without taking a detour to Monreale, you'd be missing out on one of Sicily's architectural gems. Our vote for the best day trip from Palermo, Monreale is a hilltop town just a half-hour bus ride away from the city's centre, which happens to house what most Sicily's experts regard as the Island's most beautiful cathedral. Built in the Arab, Norman and Byzantine styles, the formidable mosaics and dazzling cloister make for a memorable visit to this spiritual capital of a lost empire.