The city offers many places of special interest. As one of the oldest capital cities in Europe, it blends its past and present in a remarkable architectural style. Historic landmarks include the 10th-century Boyana Church (one of the UNESCO World Heritage protected sites), the Alexander Nevski Cathedral (one of the world's largest Orthodox churches), the Rotonda of St. George, The Banya Bashi Mosque, The Sofia Synagogue and the early Byzantine Church of St. Sophia. More modern architecture is represented by the Bulgarian National Opera and Ballet, the Ivan Vazov National Theatre, The Sts. Kilril and Metodii National Library, the Rakovski St theatre district, Slaveykov Square's outdoor book market, and the NDK, which is Southeastern Europe's largest cultural and congressional centre. There are 16 universities in the city, among them Sofia University, founded in 1888. Sofia is the see of an Eastern Orthodox and of a Roman Catholic diocese.
