Rachovets
Gorna Oryahovitsa, Bulgaria · built 300
Rahovets (Bulgarian) was an ancient Thracian, medieval and Ottoman fortress in Northeastern Bulgaria. It is located on a hill close to the town of Gorna Oryahovitsa (2 km) and Veliko Tarnovo (5 km).
Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).