Heading down the east coast of Kauai, turn inland south of Wailua on Hwy 580 to visit Opaeka'a Falls. If you're feeling adventurous, kayak or join a boat tour up the Wailua River to see the Fern ...

at Kayak Kauai at the Wailua River Marina. Then, head out for a peaceful 2.5-mile float down the river and a half-mile hike to see Secret Falls, aka Uluwehi Falls, with its 100-ft cascade.