were 166,000 pupils enrolled in elementary education and more than 13,225 teachers, giving a ratio of one teacher per 12 pupils and 20 pupils per class. Secondary After completing elementary school, nearly all children (more than 98%) go on to secondary education, either vocational, technical or general secondary programmes (gimnazija). The latter concludes with matura, the final exam that allows the graduates to enter a university. 84% of secondary school graduates go on to tertiary education. Tertiary Among several universities in Slovenia, the best ranked is the University of Ljubljana, ranking among the first 500 or the first 3% of the world's best universities according to the ARWU. Two other public universities include the University of Maribor in Styria region and the University of Primorska in Slovene Littoral. In addition, there is a private University of Nova Gorica and an international EMUNI University. Culture Heritage Slovenia's architectural heritage includes 2,500 churches, 1,000 castles, ruins, and manor houses, farmhouses, and special structures for drying hay, called hayracks (). Four natural and cultural sites in Slovenia are on the UNESCO World Heritage Site list. Škocjan Caves and its karst landscape are a protected site as the old forests in the area of Goteniški Snežnik and Kočevski Rog in the SE Slovenia. The Idrija Mercury mining site is of world importance, as are the prehistoric pile dwellings in the Ljubljana Marsh. The most picturesque church for photographers is the medieval and Baroque building on Bled Island. The castle above the lake is a museum and restaurant with a view. Near Postojna there is a fortress called Predjama Castle, half hidden in a cave. Museums in Ljubljana and elsewhere feature unique items such as the Divje Babe Flute and the oldest wheel in the world. Ljubljana has medieval, Baroque, Art Nouveau, and modern architecture. The architect Plečnik's architecture and his innovative paths and bridges along the Ljubljanica are notable and on UNESCO tentative list. Cuisine Slovenian cuisine is a mixture of Central European cuisine (especially Austrian and Hungarian), Mediterranean cuisine and Balkan cuisine. Historically, Slovenian cuisine was divided into town, farmhouse, cottage, castle, parsonage and monastic cuisines. Due to the variety of Slovenian cultural and natural landscapes, there are more than 40 distinct regional cuisines. Ethnologically, the most characteristic Slovene dishes were one-pot dishes, such as ričet, Istrian stew (), minestrone (), and žganci buckwheat spoonbread; in the Prekmurje region there is also bujta