Waimea may get lots of press for the giant winter waves in the bay, but the valley itself is a newsmaker and an ecological treasure in its own right. If you visit one botanical garden on Oahu, this is the one to see. The Office of Hawaiian Affairs is working to conserve and restore the natural habitat. Follow the Kamananui Stream up the valley through the 1,800 acres of gardens. The botanical collections here include more than 5,000 species of tropical flora, including a superb gathering of Polynesian plants. It's the best place on the island to see native species, such as the endangered Hawaiian moorhen. You can also see the remains of the Hale O Lono heiau (temple) along with other ancient archaeological sites; evidence suggests that the area was an important spiritual center. At the back of the valley, Waihi Falls plunges 45 feet into a swimming pond. Bring your suit—a swim is the perfect way to end your hike. There's a lifeguard and changing room. Be sure to bring mosquito repellent, too; it gets buggy.
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