Plovdiv is the second largest city in Bulgaria after Sofia, and is famous for its ancient culture and rich history. This ancient city, which was built around seven hills, is inhabited by the people who have preserved it in its various ancient details since the sixteenth century AD. It is filled with historical museums, art galleries, ancient huge theaters built in the Roman era, and opera houses. In addition to luxury hotels and resorts, modern entertainment and commercial centers, and local and international restaurants. As well as the old town, which is teeming with historical buildings, castles and forts, and houses dating back to the Renaissance. There are many performances, musical celebrations and festivals that attract tourists from all over the world.