Deva, capital of Hunedoara county, an industrial town with ancient legacy (former Dacian settlement of Decidava or Dacopolis) and home of the Romanian Gymnastics Olympic Team, is being watched over from the top of a volcanic hill by the citadel built in 1269.
The fortress had a long history, defending against both the invasions (such as the cumans' and later the Turkish army's attacks) and popular revolts (such as the one in 1784 led by Horia, Cloşca and Crişan). During the 1848 revolution (when Transylvania was part of the Kingdom of Hungary), terrible battles were fought here by the magyar revolutionary forces against the czar's army.
Part of the fortress was destroyed in 1849, due to an explosion in the gunpowder storehouse and today it's being reconstructed (so I couldn't take any pictures from inside).
The fortress can be reached on foot (50 minutes walk on a path that goes round hte hill) or by an aerial tramway (costs 10RON/person but it's fast). From the top of the hill one can see a magnificent view of the city and the valley of Mureş river.
Besides the old town buildings dating back to the XVIII-th century (among which is the cemetery chapel) it is worth mentioning The Bethlen Castle (Magna Curia - The Great Court). It can be found just below the citadel hill and it dates back to 1582. Nowadays it hosts the Dacian and Roman Civilization Museum.
More details regarding Deva can be found here, while the location is here and some personal photos follow: