Boiling River: Kills Everything That Falls Into It


    It sounds like a Jules Verne tale: a boiling river that seems to flow from the center of the earth and kills anything that falls into it. Andrés Ruzo, a National Geographic Young Explorer, first heard about it from his Peruvian grandfather. When Ruzo became a geophysicist, he decided to investigate whether this story could be true—and whether science could explain it.

    In an interview with national geographic, Ruzo explains what I discovered after returning from the trip to the boiling river.

    The Boiling River hovers on the boundary between scientific fact and myth—what drew you to the story?

    I first heard the story of the Boiling River as a boy in Lima from my grandfather as part of a legend of a lost city of gold in the Amazon. Much later, when I was working on my PhD in geophysics, I started looking at this detail from a scientific viewpoint. The focus of my dissertation was to create the first detailed heat flow map of Peru in order to identify areas of potential geothermal energy.

    When looking at the heat of the earth, naturally hot springs, fumaroles, and volcanoes catch my attention. One day, my colleagues from the Peruvian government called me in to look at this map they were about to publish. I took a look at it and saw there were some hot springs in the Amazon, and some of them were really quite hot. So I asked them: Hey, do you guys remember that detail in the legend about a river that boils deep in the Amazon?

    You write, “This river challenges what we think we know.” Explain that. 

    There are two levels to that. On one side, it’s the personal expectations you might have for what is possible—and what is impossible. We rely on experts, and it becomes very easy to outsource your thinking, so to speak. In a way, that’s what happened to me. I asked a bunch of experts for their thoughts about the Boiling River. Most said it’s just a legend. One professor even told me, Stop asking stupid questions; it’s making you look bad. [Laughs] But what do we really know? I think that that’s a very interesting question now more than ever. If you go online, you hear so many opinions, some that are qualified, others that are not. Wondering what you really know is a very positive exercise that we can all do.

    Where is this mysterious river? Take us through your journey. 

    The Boiling River is in the central Peruvian Amazon, in the middle of low jungle. From Lima it’s about an hour flight to the city of Pucallpa, the largest city in the central Peruvian Amazon. From Pucallpa, it was a two-hour drive mostly on red dirt roads to the Pachitea river, a tributary of the Amazon over 300 meters wide. From there, we took a peke-peke, or motorized canoe, upriver for about 30 minutes to the mouth of the Boiling River. It’s called a peke-peke because the motor goes pekepekepekepekepeke. [Laughs]

    As we approached the confluence of the two rivers, the shaman’s apprentice, who was at the prow, said, Stick your hand in! So we put our hands into the cold waters of the Pachitea. As the boat glided into this olive-green plume that was the mouth of the Boiling River, immediately the temperature went up. But there was no steam and the temperature was only like hot bath water.