Earlier this year, Roose made history by being the first person to walk across Italy's Strait of Messina – a distance of 3.6 kilometers but hundreds of meters in the air.

Gale captured the process and the work that went on behind the scenes.

He told Wednesday's "Ringvaade" he was inspired by Roose's vision but knew very little about slacklining when he started shooting.

"I wanted to capture some of what went on in the planning, because the planning was as epic, and the building of the line itself, was as challenging as what he had to do walking across it," he said.

"So I wanted to be able to put cameras in places [where] the rest of the team wasn't. That meant following his rigging team, following Jaan, up a very large tower, to be able to film some of that process. And also to be able to just spend some time 'fly on the wall' style, shall we say, capturing all of the challenges that Jaan had."

Gale said Roose was very open during the shoot, giving the crew access to his home and family life.

"We shot some wonderful material with his wife and his mother, which gave greater context to his upbringing and why he is the person he is today," the film maker told the show.

You can watch the interview, mostly in English after the introduction, below.

You can watch the documentary "Jaan Roose- Life On The Line" here.

This article was updated to add the link to "Jaan Roose- Life On The Line."

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