Don't fall in! A legendary river that BOILS its victims alive is discovered deep in the heart of the Amazon

A mysterious, four-mile long river, deep in the heart of the Amazon, is so hot that it boils.

The river has long been a legend in Peru, but when geoscientist Andrés Ruzo's heard about it, he thought such a phenomenon was impossible.

He believed that it would require a huge amount of geothermal heat to boil even a small river, and the Amazon basin is far from any active volcanoes. 

But then, Ruzo saw the legendary boiling river with his own eyes.

Ruzo first heard about the Mayantuyacu river when his grandfather told him a story about how Spanish conquistadors killed the last Inca emperor.

The story goes that after the murder, the Spanish conquistador headed into the Amazon rainforest in search of gold.

When they returned, the men spoke of a terrifying experience that involved poisoned water, man-eating snakes and a river that boils from below.

Twelve years later, at a family dinner, Ruzo heard the river mentioned again when his aunt said that she had visited it.

As a PhD student in geophysics at Southern Methodist University, Ruzo wanted to find the river for himself. 

'I began asking that question. Could the boiling river exist?, Ruzo said in Ted Talk. 

'I asked colleagues from universities, the government, oil, gas and mining companies, and the answer was a unanimous no. 

'And this makes sense. You see, boiling rivers do exist in the world, but they're generally associated with volcanoes. You need a powerful heat source to produce such a large geothermal manifestation.

'Telling this same story at a family dinner, my aunt tells me, 'But no, Andrés, I've been there. I've swum in that river.' 

Despite his skepticism, Runzo found myself hiking into the jungle in 2011, guided by his aunt, far from the he nearest volcanic center. 

He said he was mentally preparing to behold the legendary 'warm stream of the Amazon - but what he saw was very different. 

Runzo discovered a four mile 'boiling river' in the sacred geothermal healing site of the Asháninka people in Mayantuyacu. 

At its widest, it is 82ft (25 metres), and around 20ft (six metres) deep. The water is hot enough to brew tea, according to a report in Gizmodo, and in some parts, it boils over.

'Dipping my hand into the river would give me third-degree burns in less than half a second,' Ruzo told Ted.com 'Falling in could easily kill me.'

The river boils because of fault-fed hot springs.

'As we have hot blood running through our veins and arteries, so, too, the Earth has hot water running through its cracks and faults,' Runzo explained in a Ted speech.