Lush river valley with riverboat cruise (fee charged) to Fern Grotto, an unusual fern-covered cave set in a tropical garden; scenic vistas of attractive waterfalls, 'Opaeka'a Falls and Wailua Falls, and the Wailua River Valley. The Wailua Complex of Heiau (National Historic Landmark)--remains of heiau (places of worship), pu'uhonua (places of refuge), and birthstones at this once important seat of chiefly power in old Hawai'i. Picnicking in riverside coconut grove; and dining and gift shopping at Wailua Marina. - Hawaii State Parks