From the street St. John’s Co-Cathedral in Valletta is a blank honey-stone fortress; step inside and every surface erupts into carved, gilded high baroque, the floor a mosaic of inlaid-marble tombstones marking the Knights of St. John buried beneath it. The Oratory holds Caravaggio’s enormous Beheading of Saint John the Baptist — the only work the painter ever signed. With Delta now flying direct to Malta, AFAR flags it as worth booking a timed ticket ahead; the queues are real.