Historic site — Didymoteicho, ~90km north of the city
Construction began under Sultan Bayezid I and finished under his successor Mehmed I, with the mosque inaugurated in 1420 — making it one of the oldest Ottoman mosques standing anywhere in Europe, and a landmark of early Ottoman architecture in the region.
A fire in March 2017 destroyed the wooden roof and much of the interior. Restoration began in 2022, funded through Greece's Ministry of Culture and EU recovery funds at a cost of roughly €13.5 million — one of the largest timber-restoration projects in Europe, using more than 3,500 individually cut wooden pieces, with work targeted for completion around the end of 2025. Check current access before planning a visit specifically for the interior.
Even mid-restoration, the exterior and the scale of the works are worth seeing on a walk through Didymoteicho's old town, a short walk from the fortress.