At the pinnacle point of Oia is the ruined castle which was the seat of the Argyri family under the Venetians and serves as a lookout point with a complete 360-degree view. It is also called Fort Londsa. One of the most recognisable buildings in the town is an old windmill, which often appears on postcards. There are many kiosks offering a range of ethnic goods, handicrafts, jewellery and souvenirs, and several small art galleries, including Art Gallery Oia and The Art Gallery. The town also has numerous restored churches, including Panagia church; some were built in memory of sailors.