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 railway lines to Sofia, Panagyurishte, Karlovo, Peshtera, Stara Zagora, Dimitrovgrad, and Asenovgrad. There are three railway stations: Plovdiv Central, Trakia, and Filipovo as well as a freight station. Plovdiv has a large public transport system including around 29 main and 10 extra bus lines. However, there are no trams in the city, and the Plovdiv trolleybus system was closed in autumn 2012. Six bridges span the Maritsa river including a railway bridge and a covered bridge. There are important road junctions to the south, southwest, and north. Plovdiv has a well-developed cycling infrastructure which covers almost all districts of the