TORONTO -- The Masaya Volcano has been conquered.

Step by step, highwire artist Nik Wallenda inched his way across the open mouth of an active volcano in Nicaragua on Wednesday, balancing on a tightrope high above the bubbling lake of lava.

Mere metres from the end of his walk, he appeared to briefly slip, saying, “Whoa, that’s not fun,” out loud. But he tossed aside the goggles and gas mask he’d been wearing during the journey, and jogged the last few steps to touch down safely.

“Off the wire and into the history books!” he tweeted after the stunt.

He told ABC News that he felt “relieved” after the successful walk. It was the longest and highest tightrope stunt that the 41-year-old had ever attempted.

The walk was part of a two-hour TV special on ABC, which carried it live. The walk itself took approximately thirty minutes.

His wife, Erendira, is an aerialist, and also performed stunts above the volcano as part of the special. She did acrobatics while hanging from a hoop, at one point removing her gas mask to complete a stunt that saw her dangling above the volcano by her teeth.

Both had worn facial protection due to gases emitted by the volcano.

Wallenda said his eyes started to burn from gases during the walk -- his goggles weren’t sealed tight enough. But he pushed forward.

Watching the lava move underneath him was “mesmerizing,” he said.

Masaya is a caldera -- a cauldron-shaped type of crater formed by a volcano collapsing in on itself -- with an active lava lake 548 metres wide. In an interview in January, Wallenda said that he’d trained for the stunt with a smoke machine to simulate some of the conditions he’d be facing.

He said that although he’d prepared for unpredictable winds, they were the hardest thing to deal with. Throughout the walk, a live feed showed him occasionally pausing to pray as winds buffeted him.

“There was a time where I was taking a step, and I felt like I got knocked back and I was like, ‘Oh my gosh, I hope I get my foot back around there in time’,” he said.

He described the gusts as stronger than anything he’d felt walking across the Grand Canyon, one of his previous tightrope stunts.

Wallenda is a seventh-generation acrobat, who comes from a family of star tightrope-walkers.

He is known for foregoing safety precautions in his stunts, but did wear a harness and tether for the volcano walk, after saying he hoped he wouldn’t have to. He told the Sarasota Herald-Tribune that ABC insisted he wear the harness, as he had during a previous televised stunt crossing Times Square on a tightrope.