The Hawaii Volcanoes National Park on The Big Island (Hawaii) is a great place to see nature's most powerful force in action. The most active volcano Mauna Loa erupts more or less constantly, and the boiling hot lava being thrown up into the air is a sight that you will never forget. In common with all US National Parks, there is excellent trekking in the area on well-marked footpaths, as well as opportunities to camp out and cycle. The top of the mountains can be very cold - away from the crater, and visitors are advised not to stand too close to the action to avoid getting hit.
