4. Plitvice Lakes National Park (Croatian: Plitvička jezera) is the oldest and the largest national park in Croatia. The national park is world famous for its 16 lakes arranged in cascades and waterfalls. These lakes are separated by natural dams of travertine rock, which is the result of an interplay between water, air and plants..

11. Lake Vrana (Croatian: Vransko jezero) in Dalmatia is the largest lake in Croatia. It is a designated nature park, a kind of protected area in Croatia. It is an ornithological reserve, an almost untouched natural habitat of birds.

12. The area of the lake is about 30 square kilometres, but it is only 4 metres deep.

14. Lake Vrana, in the centre of Cres, is a fresh water lake, that supplies islands Cres and Lošinj with drinking water.

15. The lake is 1.5 km wide, 7 km long and it is cryptodepression. Its bottom reaches a depth of around 60 m below the sea level, but its surface lies 14 m above it. First it was thought that the water in the lake was linked to some mainland source by underground streams, but its water originates from rain.

18. Red Lake and Blue Lake (Croatian: Crveno i Modro jezero ) are two karst lakes located near the town of Imotski in the south of Croatia. They lie in deep sinkholes possibly formed by the collapse of large underground caves.

19. Red Lake

20. Blue Lake

21. Water depth varies over seasons. At the end of summer, Blue Lake may completely disappear. The average water depth of Red Lake is 290 meters.

23. Black Sea Adriatic Sea

24. The Danube River (Croatian: Dunav), the Drava (Drava), the Sava and the Kupa are long, slow and muddy. They meander through the Panonian plain.

25. The Danube River (Croatian: Dunav)

26. Kopački rit – a swamp area at the river mouth of the river of Drava (Croatian: Drava)

28. Rivers that flow to the Adriatic Sea (the Zrmanja, the Krka, the Cetina, the Neretva…) are short, fast and clear. They form gorges in the Dinaric Alps.

30. Krka waterfalls

31. In the karst areas of Croatia (the Dinaric Alps), rivers may disappear through sinkholes, continuing underground. Subterranean rivers (the Gacka, the Lika, the Dobra and the Pazinčica) are rivers that run partly beneath the ground surface.

34. These subterranean rivers are often connected to submarine karst springs in the Adriatic Sea that are called vrulje in Croatian.

35. SUBMARINE KARST SPRING VRULJA

36. 8th graders have made this presentation using school literature and Internet during Geography lessons.