Terrifying video of a slackliner walking between two cliffs over huge waves in Nazaré, Portugal.

The footage, captured on December 16, shows a member of the slacklining group the "Western Riders" Joshua Leupolz, 26, being swept off the line by one of the waves.

"According to Emerson Machado, a member of the Western Riders, the line was installed days before a big swell arrived in Nazaré, and everything was cautiously planned, checked and re-checked to provide the maximum level of security possible to the slackliners performing the walk," the filmer told Newsflare.

“It’s calculated risk, we are not crazy like it may seem at first sight, in reality, everything was planned to the very minor details. Over the years, we’ve performed walks in many locations before, including Nazaré and we take this very seriously” says the member of Western Riders.

Nazaré, December 16, 2017

A group of Slackliners called the “Western Riders” recently installed a line connecting the Cliff of Praia do Norte in Nazaré to the “Guilhim” Rock, a famous landmark known from viral photos of huge wave impacts and water explosions during the Portuguese Big Wave Season.

According to Emerson Machado, a member of the Western Riders, the line was installed days before a big swell arrived in Nazaré, and everything was cautiously planned, checked and re-checked to provide the maximum level of security possible to the slackliners performing the walk. “It’s calculated risk, we are not crazy like it may seems at first sight, in reality everything was planned to the very minor details. Over the years, we’ve performed walks in many locations before, including Nazaré and we take this very seriously” says the member of Western Riders, “over the course of two days, we’ve performed dozens of walks between the cliff and the rock in Nazaré, and no one was ever injured during that time, it’s relatively safe when performed by an experienced crew, working together with planning and caution” he adds.

This extreme sport is called “Slacklining”, and this version performed in Praia do Norte is called “Highlining”, it involves balancing on a rope that's suspended above the ground (or above the sea in this case) and anchored between two points. It looks like a sport made for daredevils, but well trained slackliners believe all the gear and equipment they use is all made, tested and certificated for this activity, making it perfectly safe.

The Slackliner on this video was identified as Joshua Leupolz, 26 years from Germany.

Praia do Norte beach, near the fishing village of Nazaré, has become famous for huge waves since Hawaiian surfer Garrett McNamara set a then record in 2011 for the largest wave ever surfed when he rode a 78-foot wave. Since then, the place has attracted many daredevils from a great variety of extreme sports.