Transcript for Vacation warning near other volcanoes
Back with a closer look at volcanoes after that eruption in New Zealand, new concerns this monk about other popular tourist spots around the world. Matt Gutman is at one of those sites, saltonbuttes. Reporter: There are five active volcanoes here and until recently geologists thought they last erupted 30,000 years ago. Recently they learned it was about 2,000 years ago and in geological terms that's a Billick of an eye and that's what makes volcano tourism so potentially dangerous. Volcanoes are unpredictable. Volcanoes are a part of new Zealand's tourism. This peak attracting 10,000 people a year. This one featured in "The lord of the rings" movies but predicting volcanic eruptions is nearly impossible. There are 1500 potentially active volcanoes worldwide, some closer than you think. There are 169 active volcanoes in the United States. Some of them are massive mountains that loom over cities as mount St. Helens does over Portland and Seattle. Others right under your feet and the majesty and spectacle of these phenomena seem to have spurred tourism. But with at least 18 dead or presumed dead on Monday's eruption on white aisle, there is mounting concern about other volcanoes accessible to vacationers. This volcanologist says most are not aware of the dangers and they are very real. We were in Hawaii during the jarring kilauea volcano eruptions in 2018 facing fountains of lava and magma. Heat radiating off this fissure is incredible. That has been gushing lava into the air for three consecutive days. Reporter: Accompanying that molten lava clouds of toxic fumes. We saw the dangers of volcano tourism there as well. A so-called lava bomb from that eruption smashing through a sightseeing boat's roof injuring two dozen people. A huge chunk of lava. Reporter: Dr. Lee and his wife a former trauma nurse were on that boat in Hawaii and jumped in to help the injured. As that fateful trip reminds those tours don't guarantee's one safety. Just because a tour is offered it doesn't necessarily guarantee your safety. Life is beautiful. We can see the beauty all around us but maybe we don't need to get that close to it. Reporter: Guys, having witnessed the power of mother nature in volcanoes myself I know it inspires awe but ultimately it's up to each individual tourist, whether the spectacle is worth the risk. Guys. Yeah, sure is. Dangerous.
This transcript has been automatically generated and may not be 100% accurate.