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 HawaiÊ»i. Picnicking in riverside coconut grove; and dining and gift shopping at Wailua Marina.