Historic site — Kirki, ~45km northwest of the city
The village of Kirki grew up around one of the largest mining operations in the wider region — a complex of lead, zinc, and other polymetallic deposits worked across an area of roughly 118 square kilometres. Mining ran almost continuously through the 20th century before the operation closed for good in 1997.
The abandoned mine buildings and workings sit a few kilometres outside the village itself, a stark contrast to the wooded hills around them — an industrial-heritage site rather than a polished attraction, so go with realistic expectations about access and signage.
Best treated as a detour on the way to or from Dadia Forest, which lies in the same general direction from Alexandroupolis, rather than a dedicated day trip.