As a child, Andrés Ruzo, a geothermal scientist from Lima, Peru, heard legends of the Spanish conquistadors’ failed quest to discover the lost city of gold. They were peppered with colorful details, ranging from man-eating snakes to a boiling river in the Amazon. Ruzo initially dismissed the tales as myths, according to Gizmodo, but while creating a geothermal map of Peru in graduate school, he began wondering if there was any truth to the anecdote about the boiling river. As a new video from Great Big Story details, there was: He eventually located a hidden Peruvian river that's hot enough to kill.

In 2011, family members led Ruzo to the 82-foot-wide, steaming river tucked deep in the remote rain forest. The site is considered sacred by locals, and is home to multiple traditional healing centers.

But this isn't your average hot spring. The water's intense heat comes from a geological fault, according to Science Alert. Although Ruzo’s aunt and mother have safely ventured into its waters after cool, heavy rainfall, he cautions against taking a casual dip. The hottest temperature he’s ever measured was more than 210°F, the scientist told Great Big Story—just a few degrees short of the boiling point. The river runs hot enough to burn for almost 4 miles, and will essentially cook alive any animal that falls into it. “You stick your hand in, and you will see second and third-degree burns in a matter of seconds.”

Learn more about the real-life wonder, detailed in Ruzo's 2016 book The Boiling River: Adventure and Discovery in the Amazon, by watching Great Big Story’s video below.