Santa Maria dello Spasimo is the most unusual sight in Palermo: an unfinished, roofless Gothic church in the Kalsa, now used as an open-air venue for jazz, exhibitions, and contemporary performances. The Gothic nave is intact, walls and rib vaults reaching almost to where the roof should be, with sky open above the central crossing.
Trees grow inside, palms in the side chapels. The setting is genuinely moving — a few minutes' walk from the noisy Foro Italico, but feeling like a clearing in a private wood. Free entry, open most daylight hours. Check the cultural programme for evening events.