The United States is brimming with natural wonders, and the most dramatic of them all were formed from volcanic forces deep beneath the Earth's surface.
Many of these explosive creations have settled and cooled over the course of millennia to form snaking lava tubes or surreal columnar basalt, but countless other sites still burn — active, volatile testaments to the ever-changing beauty of our planet.
Naturally, these volcanic and geothermal areas, many of which are contained in national parks, are wildly popular with tourists looking to add a little punch to their summer road trips. Here's a look at three national parks that can easily burn you if you aren't careful.
1. Lassen Volcanic National Park
Located in northeastern California, Lassen Volcanic National Park straddles a fine line between lush, flowery meadows and an array of boiling and bubbling hydrothermal features. Its fascinating volcanic geology is the result of its unique location: surrounded by the Cascades range in the north, the Sierra Nevadas in the south and the Great Basin desert in the east.
According to the National Park Service, "the myriad habitats of [the area] are produced by variations in environmental conditions such as elevation (5,000 to 10,457 feet), moisture (precipitation is greater on the western than the eastern side of the park), substrate (rock type and soil depth), temperature, insolation (amount of sun) and prior disturbance (both natural and human-caused)."
2. Hawai'i Volcanoes National Park
When we're talking volcanic tourism in the U.S., there's no way you can leave out the ferocious beauty of Hawaii's Kilauea.
This shield volcano, which first broke above sea level 100,000 years ago, is found on the Big Island, where it has erupted multiple times since its activities were first officially recorded in the 18th century. Most recently, the volcano began erupting again in 1983, and it continues to spew at a steady rate.
As part of Hawai'i Volcanoes National Park, Kilauea is easily accessible to tourists looking to see molten lava in person. In the interests of safety (and common sense), some portions of the park are indefinitely off-limits, though you can monitor updates on volcanic activity on the NPS website. Most recently, a lava flow reached the Pacific Ocean, making for a jaw-dropping, rare sight.
3. Yellowstone National Park
Sure, Hawaii may have active volcanoes with flowing lava, but Yellowstone really knocks it out of the ballpark with its outstanding array of colorful hot springs, exploding geysers, simmering mudpots and steaming fumaroles.
The crown jewel of the park is undoubtedly the Grand Prismatic Spring (pictured above), a microbe-rich pool that lays claim to being the largest hot spring in the country (and the third largest in the world). Yet another centerpiece of the park is, of course, Old Faithful:
This famous cone geyser is capable of expelling between 3,700 and 8,400 gallons of superheated water. While the geyser is, indeed, quite faithful, it doesn't run like clockwork. Eruption intervals actually range from 60 to 110 minutes, and the duration of each episode is typically either 1.5 or 4.5 minutes.
According to the National Park Service, the geyser "currently erupts around 17 times a day and can be predicted with a 90 percent confidence rate within a 10 minute variation."
Those are just three fiery national parks we think you should add to your bucket list, though there are undoubtedly many more hot spots throughout both North America and the world at large! What are some of your favorites that we didn't list?