Church of Paraportiani.

Standing at the edge of the Kastro neighborhood, the Church of Panagia Paraportiani is a masterclass in organic architecture. Its name, meaning "standing next to the entrance door," refers to its historical position beside a medieval castle gate. Rather than a single building, this starkly whitewashed landmark is a cluster of five separate churches fused together over two centuries. Four chapels form the base—Agios Efstathios, Agios Anargyros, Agios Sozon, and Agia Anastasia—while the fifth, dedicated to the Virgin Mary, sits on top like a central dome. The result is a sculptural, asymmetrical form that blurs the lines between Byzantine tradition and vernacular Mediterranean style. Its smooth, undulating walls have made it one of the most photographed sites in the Aegean.