Waimea Falls was once a kitschy theme park that featured cliff divers and hula dancers. Now peaceful nonprofit gardens reign here, alongside one of the best hikes in Oahu. The flat 1.6-kilometer (one-mile) trail barely lives up to the energetic label of "hike," though. Instead, it's more of a pleasurable stroll through a lush and thoughtfully curated landscape. Take your time and marvel at the oversize, bright tropical plants towering overhead before you emerge at the showstopping 15-meter (49-foot) cascade. Feeling adventurous? Take a dip in its freshwater pool.