Kauai's South Shore Spouting Horn, named for the sound it makes when the water rushes up, is a natural phenomena just a five-minute drive from Kiahuna Plantation. The sound is created when incoming waves crash against the shore and water is forced up through old lava tunnels to the surface of the rock outcropping below the lookout.
At Spouting Horn, on the lawn near the parking lot, you will also find many vendors selling local arts as crafts. Directly across the street is the Allerton Botanical Garden. The garden was designed by Robert and John Allerton. There is a nominal entrance fee which helps pay for upkeep of the landscaped grounds by the National Tropical Botanical Garden.
Waimea Canyon is another one of Kauai's natural phenomena. Called the "Grand Canyon of the Pacific", there are several overlooks along the road offering breathtaking, scenic views of not only the canyon but also of Niihau, the forbidden island.
At the end of the Waimea Canyon road is the Pu'u o Kila Lookout in Kokee State Park. Here you can take in the unobstructed panoramic views of the Na Pali Coast. This side of the island is virtually uninhabited as there are no roads connecting the southwest of Kauai to the northwest. The wettest spot on earth is located near the center of Kauai.