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 European mosque outside Moorish Spain. The Sephardic Plovdiv Synagogue is at Tsar Kaloyan Street 13 in the remnants of a small courtyard in what was once a large Jewish quarter. Dating to the 19th century, it is one of the best-preserved examples of the so-called "Ottoman-style" synagogues in the Balkans. According to author Ruth E. Gruber, the interior of the Plovdiv Synagogue is a "hidden treasure…a glorious, if run-down, burst of color." An exquisite Venetian glass chandelier hangs from the center of the ceiling, which has a richly painted dome. All surfaces are covered in elaborate, Moorish-style, geometric designs in