Plitvice lakes

Plitviče Lakes National Park is a 295-sq.-km forest reserve in central Croatia. It's known for a chain of 16 terraced lakes, joined by waterfalls, that extend into a limestone canyon. Walkways and hiking trails wind around and across the water, and an electric boat links the 12 upper and 4 lower lakes. The latter are the site of Veliki Slap, a 78m-high waterfall. ― Google