natural border between Bosnia and Herzegovina and Serbia, and represents the main kayaking and rafting attraction in both countries. Due to configuration of the terrain, natural lakes are sparse and small; most of them are located in the lowlands of Vojvodina, like the aeolian lake Palić or numerous oxbow lakes along river flows (like Zasavica and Carska Bara). However, there are numerous artificial lakes, mostly due to hydroelectric dams, the biggest being Đerdap (Iron Gates) on the Danube with on the Serbian side (a total area of is shared with Romania); Perućac on the Drina, and Vlasina. The largest waterfall, Jelovarnik, located in Kopaonik, is 71 m high. Abundance of relatively unpolluted surface waters and numerous underground natural and mineral water sources of high water quality presents a chance for export and economy improvement; however, more extensive exploitation and production of bottled water began only recently. Environment Serbia is a country of rich ecosystem and species diversity—covering only 1.9% of the whole European territory, Serbia is home to 39% of European vascular flora, 51% of European fish fauna, 40% of European reptiles and amphibian fauna, 74% of European bird fauna, and 67% European mammal fauna. Its abundance of mountains and rivers make it an ideal environment for a variety of animals, many of which are protected including wolves, lynx, bears, foxes, and stags. There are 17 snake species living all over the country, 8 of them are venomous. Mountain of Tara in western Serbia is one of the last regions in Europe where bears can still live in absolute freedom. Serbia is home to about 380 species of birds. In Carska Bara, there are over 300 bird species on just a few square kilometres. Uvac Gorge is considered one of the last habitats of the Griffon vulture in Europe. In area around the city of Kikinda, in the northernmost part of the country, some 145 endangered long-eared owls are noted, making it the world's biggest settlement of these species. The country is considerably rich with threatened species of bats and butterflies as well. There are 380 protected areas of Serbia, encompassing 4,947 square kilometres or 6.4% of the country. The "Spatial plan of the Republic of Serbia" states that the total protected area should be increased to 12% by 2021. Those protected areas include 5 national parks (Đerdap, Tara, Kopaonik, Fruška Gora and Šar Mountain), 15 nature parks, 15 "landscapes