Belogradchik Fortress, Bulgaria
The Belogradchik Fortress, with its walls that are 2 metres thick and up to 12 metres high, is a popular Bulgarian tourist attraction.
Also known as Kaleto, it is a culturally and historically significant monument, since it is one of the best preserved strongholds in Bulgaria.
Located on the northern slopes of the Balkan Mountains and about 40 km from the Danube, a visit to Belogradchik Fortress is an optional excursion on a Danube River Cruise (or a road-trip in Eastern Europe), along with a visit to Baba Vida fortress.
If not part of a guided excursion, check visiting times before travelling to this wonderful piece of history and geology, as it may close early on holidays.

If you’re active, it’s worth climbing the 200+ steps to the top of Belogradchik Fortress. The view of the lower levels of the fortress and surrounding landscape and town is quite impressive.