Plitvice Lakes National Park is the oldest national park in Southeast Europe and the largest national park in Croatia. The park was founded in 1949 and is situated in the mountainous karst area of central Croatia, at the border to Bosnia and Herzegovina. The protected area extends over 296.85 square kilometres (73,350 acres). In 1979, Plitvice Lakes National Park was added to the UNESCO World Heritage register and was among the first natural sites worldwide. Each year, more than 1,200,000 people visit the national park.

The national park is world famous for its lakes arranged in cascades. Currently, 16 lakes can be seen from the surface. These lakes are a result of the confluence of several small rivers and subterranean karst rivers. The lakes are all interconnected and follow the water flow. They are separated by natural dams of travertine, which is deposited by the action of moss, algae, and bacteria.

The sixteen lakes are separated into an upper and lower cluster formed by runoff from the mountains, descending from an altitude of 636 to 503 m (2,087 to 1,650 ft) over a distance of some eight kilometers. The lakes are renowned for their distinctive colors, ranging from azure to green, grey or blue. The colors change constantly depending on the quantity of minerals or organisms in the water and the angle of sunlight. [Source: Wikipedia]

For more incredible pictures of this beautiful park, check out this Sifter post from 2009!