The Lakes and National Park at Plitvice are magnificent. Wooden walkways cross the still glassy clear lakes and at some points you can look down and see a vertical forest of fallen trees. The paths take you close to the stunning waterfalls but are done in a way that doesn't feel intrusive. Great for a days walking as an excursion from the coast.
A couple of hours drive from the coast.
Take a bus from Zagreb main bus station, there was one per hour when I went. Busses back not weren't so reliable, but the service has probably improved now. Journey is around an hour and takes you through the Croatian countryside still scarred by the conflicts.
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