Photograph by Hans Madej, laif/Redux

Croatia's 1,104-mile (1,776-kilometer) island-speckled Adriatic coast is a popular playground for sea kayakers, sailors, kite surfers, and divers. Additional water wonders await those willing to travel inland (a four-hour bus ride from the coast) to the mountainous, eastern Plitvice Lakes region, site of Croatia’s first and largest national park.

Nature's color wheel is in constant motion at 114-square-mile (296-square-kilometer) Plitvice Lakes National Park (above) where 16 terraced lakes, formed by natural travertine dams, change hues throughout the day from bright turquoise to gray depending on the angle of the sun's rays and mineral makeup of the water. Well-maintained wooden boardwalks and trails link the lakes to the park’s centerpiece cascades, the largest of which—Big Waterfall—plummets 256 feet (78 meters) into the valley below. Home to abundant wildlife, including 261 species of birds, the walker-friendly park is divided into Upper and Lower Lakes sections bridged by the Lake Kozjak ferry.