Tucked into the Dinaric Alps of central Croatia, roughly halfway between Zagreb and the Adriatic coast, a chain of 16 terraced lakes spills down a limestone valley in a cascade of waterfalls that have been forming and reforming for millennia. Plitvice Lakes National Park covers nearly 30,000 hectares, making it roughly the same footprint as the city of Amsterdam, and it has been Croatia's largest and oldest national park since 1949.