Zipline Beware of the Bear
If ziplines are your thing, prepare for something special. At 1700m, Beware of the Bear is Europe's longest one-piece zipline. Under the right wind conditions, you'll reach speeds of up to 120km/h as you zip 80m above the earth. It really does feel like flying.
Climbing, cycling and disc golf are also available, but they're positively tame by comparison.
Zipline Beware of the Bear is in Rudopolje-Vrhovine, around 44km by road west of the main entrance to Plitvice Lakes National Park. You'll need your own car to get here.