remains of the builings in the ancient roman city of diokletianopolis, hisarya, plovdiv region, bulgaria

remains builings ancient roman city diokletianopolis hisarya plovdiv region bulgaria town hisaria hissarya hissaria hisar hissar sredna gora mountain mineral water resort spa fortress wall fortification ruins stone archeology archeological architecture sightseeing byzantine diokletian structure europe tourism vacation sights landmark destinations park outdoor brick historical thrace