In recent years slackline, a sport similar to tightrope walking, has become increasingly popular. It’s also been taken to extreme new heights. Case in point: the two people who walked over an active volcano with nothing but a small piece of cloth underneath your clothes sounds terrifying. In April of 2020, Rafael Zungo Bridi and Alexander Shulz broke a Guinness World Record for the longest slackline over an active volcano. The company recently released video of the feat.

Bridi, from Brazil, and Shulz, from Germany, walked 856 feet across Mount Yasur, a stratovolcano on Tanna Island in Vanuatu, at the height of 137 feet above the crater. “Lavaline Project” was Schulz’s idea. He was inspired by his father, who’s a volcanologist. Yasur has been continuously erupting since at least 1774. The logistics of the Lavaline Project came with its challenges. The pair considered the Erta Ale in Ethiopia, the Masaya in Nicaragua and the Nyiragongo in the Democratic Republic of Congo before settling on Yasur. Once they arrived, the two had to slackline in extreme humidity and acid rain while red hot lava poured and spewed out toxic fumes.

Bridi also holds the world record for the highest slackline walk set in December 2021 when he walked 59 feet on a one inch slackline between two hot-air balloons at an altitude of 6,236 feet above Praia Grande in Santa Catarina, Brazil. The altitude was twice that of the world’s tallest building, the Burj Khalifa. Both records were ratified by the International Slackline Association (ISA).

If slacklining looks like something you’d be interested in, you don’t have to do it high in the sky or over lava. Practicing in your backyard or local park is a great way to start.