Roman legionary fortresses in Bulgaria

Silistra ( ; ; or ) is a town in Northeastern Bulgaria. The town lies on the southern bank of the lower Danube river, and is also the part of the Romanian border where it stops following the Danube. Silistra is the administrative center of the Silistra Province and one of the important towns of the historical region of Dobruja.

thumb|right|250px|The northern Balkans, including Ratiaria in Dacia Ripensis, in the 6th century

thumb|Local map thumb|The mosaic "The Achaeans of Menander", found near the Temple of Fortuna in Ulpia Oescus, Pleven Museum thumb|A caryatid from Ulpia Oescus, Pleven history museum thumb|Fragment of fresco from the civic basilica of Ulpia Oescus, Pleven Museum

ancient fortress archaeological site in Bulgaria