Plovdiv of which are high. Because of these hills, Plovdiv is often referred to in Bulgaria as "The City of the Seven Hills". Plovdiv is host to a huge variety of cultural events such as the International Fair Plovdiv, the international theatrical festival "A stage on a crossroad", the TV festival "The golden chest", and many more novel festivals, such as Night/Plovdiv in September, Kapana Fest, and Opera Open. There are many preserved ruins such as the ancient Plovdiv Roman theatre, a Roman odeon, a Roman aqueduct, the Plovdiv Roman Stadium, the archaeological complex Eirene, and others. The oldest American educational
Plovdiv Province capital is the city of Plovdiv; other towns include Karlovo, Sopot, Klisura, Kalofer, Hisarya, Saedinenie, Rakovski, Brezovo, Stamboliyski, Krichim, Perushtitsa, Sadovo, Parvomay, Asenovgrad, Laki, Katunica, Yiagodovo. Plovdiv Province had a population of 715,904 (715,816 also given) according to a 2001 census, of which were male and were female. As of the end of 2009, the population, announced by the Bulgarian National Statistical Institute, numbered 701,684 of which are over 60 years of age. The following table represents the change of the population in the province after World War II: Total population (2011 census): 683 027<br> Ethnic groups (2011 census): Identified