Within the boundaries of this heavily forested national park, 16 crystalline lakes tumble into each other via a series of waterfalls and cascades. The mineral-rich waters carve through the rock, depositing tufa in continually changing formations. Clouds of butterflies drift above the 18km of wooden footbridges and pathways that snake around the edges and across the rumbling water.
It takes upwards of six hours to explore the lakes on foot, or you can slice two hours off by taking advantage of the park's free boats and buses (departing every 30 minutes from April to October). From Entrance 2, catch the bus to the top of the upper lakes and wander back down to the shore of 4km-long Kozjak, the park's largest lake. A boat will whisk you from here to the lower lakes, where the circuit culminates in the aptly named Veliki Slap, the tallest waterfall in Croatia (78m). The path then climbs steeply (offering great views and photo opportunities) to a bus stop, where you can grab a lift back to Entrance 2.
If you've got limited time, the upper lake section can be completed in two hours. The lower section takes about three, although it's best to start with the bus ride and end with the boat to save yourself a climb.
Swimming is not permitted in any of the lakes.