Hawaii Volcanoes National Park beats out all the other U.S. national parks on two scores: It has the only tropical rainforest, and it has the only active volcano. Since 1983, the Big Island's Kilauea volcano has been erupting regularly, although these are "quiet"' eruptions, with gas escaping slowly instead of exploding violently. Its slow-moving red lava oozes over the landscape, sometimes even over the park roads. The kids may wish they could see volcanic fireworks, but once they're here, feeling the soles of their sneakers getting gummy from the heat below, they'll realize this is spectacular enough.
This is not a tame volcano, not by any means. Over the past 2 decades, some $100 million worth of property has been destroyed by the eruptions, though the lava flow has also added 560 acres of new land. On many days, the lava flows right alongside accessible roads and you can get as close as the heat will allow. Thanks to sulfur dioxide gas from a new vent that opened in Halemaumau Crater in March 2008, a section of the park's Crater Rim Drive is currently closed to visitors. You can still see a large portion of the park, however, including the fuming vent (from a safe distance), and most kids will be excited at the chance to experience nature in action.
Near the visitor center, you can get your first glimpse of Kilauea Caldera, a 2[bf]1?2-mile-wide, 500-foot-deep pit with wisps of steam rising from it. Going counterclockwise on Crater Rim Road, you'll drive past the Sulphur Banks, which smell like rotten eggs, and the Steam Vents, fissures where trails of smoke, once molten lava, escape from the inner reaches of the earth. At the Thomas A. Jaggar Museum, there's a viewpoint for Halemaumau Crater, which is half a mile across but 1,000 feet deep; in 2008, a new fuming vent opened in this long-dormant fire pit, which can be viewed safely from the museum overlook. Near the Iki Crater, the .5-mile Devastation Trail is a sobering look at how a volcanic eruption wreaked havoc in 1959. Another intriguing stop is the Thurston Lava Tube, a cool underground hole in a lush forested bowl that somehow escaped the lava flow.
By now you won't be surprised to learn that the volcano goddess, Pele, was an important deity to ancient Hawaiians -- you definitely wanted to be on the right side of this lady. At the 15-mile mark down Chain of Craters Road, you can see Puu Loa, an ancient site sacred to the Hawaiians, where a 2-mile boardwalk loop trail will show you thousands of mysterious Hawaiian petroglyphs carved in stone.
If the volcano is actively erupting, call the visitor center for directions to the best locations for night viewing -- it's quite a sight, watching as the brilliant red lava snakes down the side of the mountain and pours into the cold sea, hissing and steaming ferociously. Of course, the ultimate view is from the sky: Blue Hawaiian Helicopter (tel. 800/745-BLUE or 808/961-5600; www.bluehawaiian.com) runs several tours right over the bubbling caldera, for a bird's-eye view you'll never forget.
Nearest Airport: Hilo International, 29 miles.
Where to Stay: $$ Kilauea Lodge, Old Volcano Rd., off Hwy. 11 (tel. 808/967-7366; www.kilauealodge.com).