Best Faux Springs
Credit: Bob Abraham / Getty Images

For all its geothermal pyrotechnics, Hawaii has relatively few actual hot springs and none that can remotely rival the Pools of Oheo, which offer hikers along the Pipiwai Trail the opportunity to steep in tiered tubs of fresh river water. Though they're not heated beneath the surface, the pools do owe their warmth largely to volcanoes. They are made largely out of igneous rocks that hold the heat from the bright Hawaiian sun, keeping the water temperate even at night, when the stars (and locals) come out. The scene is made all the more memorable by the lush forest and the 400-foot Waimoku falls that cascade down the slope of Haleakala a short hike away. Normally tranquil, the area can be dangerous and is best avoided during heavy rainfall.