Last December, 28-year-old Emerson Machado from Brazil slacklined over angry-looking waves in Nazaré, Portugal, and the incredible moment was caught on camera.

Emerson is a member of the Western Riders, a group of slackliners who installed a rope connecting the cliff of Praia do Norte in Nazaré to the Guilhim Rock.

The maneuver sounds and looks incredibly dangerous, but it is something that Emerson is extremely experienced in.

“It’s a calculated risk. We (the team) are not crazy like it may seem at first sight. In reality, everything was planned (down) to the very minor details. Over the years, we’ve performed walks in many locations, including Nazaré and we take this very seriously,” he explained. Credit: Máquina Voadora via Storyful