By contrast, lava caves, widely known as lava tubes, are formed in a geological instant—a year or two, sometimes weeks—by an eruption from the Earth’s crust. Most of Hawaii’s lava tubes ...

Approximately 700,000 years ago when molten rock erupted from a vent in nearby Hart Prairie, the mile-long Lava River Cave was formed. Today, visitors can explore the cave's cool, dark expanse by ...