After kayaking up the Wailua River in Kaui, Hawaii, we hiked through a tropical rain forest on a challenging trek that, in some places, had mud that was knee-deep (not kidding. It looked like we were wearing boots.)
We arrived at a 120-foot waterfall called Secret Falls, had lunch and a swim. The cold water and mist from the falls was delightful after the long hike.
Then back on the trail and through the mud, into the kayaks and paddle 4-miles back to shore. It was a wonderful adventure.