Inside Palermo's Palazzo dei Normanni (the Norman Royal Palace, now Sicilian Parliament), the Cappella Palatina (1132-43) is a chapel where 3 civilizations merged to create the most densely decorated interior in the Mediterranean. Byzantine golden mosaics cover the walls (Christ Pantocrator in the dome). An Islamic muqarnas (honeycomb) ceiling of carved and painted wood — unique in a Christian church. Norman architecture frames both traditions. The BBC called it "the most beautiful room in the world." They were not exaggerating.
The mosaics: 6,340m² of gold tesserae — Christ Pantocrator in the apse, biblical narratives on the walls (Genesis, Christ's life, Peter and Paul), each figure outlined in vivid color against hammered gold. The ceiling: Islamic muqarnas — 750 painted wooden cells depicting Muslim court life (musicians, dancers, drinkers, hunters) INSIDE a Christian chapel. Norman tolerance + Byzantine craft + Islamic art = the most multicultural room ever built.
Practical: Piazza del Parlamento 1, Palermo. €14 (palazzo + chapel). Open Mon-Sat 8:15am-5:40pm, Sun 8:15am-1pm. Duration: 1-1.5h. Arrive at opening — the chapel is tiny and fills fast.