PLITVICKA JEZERA, CROATIA - JULY 06: A boat crosses Kozjak lake at Plitvice Lakes National Park on July 6, 2015 near Plitvicka Jezera, Croatia. Plitvice Lakes National Park is Croatia's largest national park and is listed as a UNESCO World Heritage site. It is a popular tourist destination for its waterfalls and turquoise coloured lakes. (Photo by Matej Divizna/Getty Images)
