This is quite possibly the most adrenaline-filled video you'll watch today.
Mountain runner Kilian Jornet, one of the strongest and fastest mountain runners ever, raced famous mountaineer and base jumper Tom Erik Heimen up and down the iconic Romsdalshorn in Norway.
The race was captured on film and makes forincredibly compelling viewing.
The two mountain experts begin at the bottom of the peak and race up and down it from opposite sides. At one point, as Jornet begins his "run" down, he passes Heimen, who's a lot further up than Jornet would have liked.
Posted to YouTube two days ago, the video has had more than 150,000 views.
"Whoever schemed this 'race' absolutely nailed it. That almost could not have been more close a finish! How thrilling. And incredibly beautiful. And astoundingly terrifying. Champions," a YouTube user commented.
"Such a nice 'down to earth' competition. No unnecessary added drama," another commenter said.
"That was fantastic to watch - amazing how close it was at the end too! Well done both of you," someone else added.
Filmed by Raymond Aasen and Matti Bernitz, the short film captures the adrenaline of the two men trying to nail their respective disciplines to prove who can be fastest.
Starting from the trailhead, they both climbed the 1550m mountain, with Jornet taking its north face and coming down the Halls Renne.
Heimen, one of the world's most experienced base jumpers and a skilled mountaineer, went up Halls Renne and flew over the north face.
Jornet holds the fastest known time (FKT) for the ascent and descent of some of the world's toughest and most iconic summits, including the Matterhorn, Mont Blanc and Mt Everest.
"Tom Erik and I had been skiing together the last years, and during the summer we meet many times in Romsdalshorn, him to base jump and me to run, so it became natural to do something together in our own way, and the idea of this challenge came straight away," the runner wrote in the YouTube caption.
You'd assume the guy flying down the mountain would have the advantage. Photo / YouTube
"It was very unpredictable who would be faster. I knew I could climb much faster, but the downhill is down climbing so it takes as much time as going up for me. And I also knew that Tom Erik have a very good physical level, so he would be quick to climb and of course very fast on the way down. During my whole descent I was expecting at any second to hear him fly by me.
"Being in the mountains with Kilian is truly motivating. He has a capacity, playfulness and motivation I have never seen before. Our common fascination for the mountains is the passion and dedication to what we do. He has shown me new dimensions on how to explore the mountains. Our adventures in skiing has given me great experiences," Heimen said.
"The Romsdalshorn Challenge is an expression of how we can use the mountains for training and as a playground. What surprised me most with the challenge was how fast Kilian is descending the technical and steep, Halls renne, with the challenges of loose rocks all the way. I know he is very fast going up, and had no doubts that he would beat me to the summit, but I was expecting him to spend more time climbing down than climbing up. When I was summiting in only 46 minutes, my personal best ever, I was 100 per cent certain that I would beat him to the finishline. During my flight back down I was constantly looking for Kilian, and when I realised how far he had come I was super surprised. I am truly amazed by this fantastic athlete."
Heimen carried 12.2kg of gear to the top of the mountain, including his wingsuit, parachute, helmet, goggles, camera and GPS device.
Jornet, who ran down while Heimen flew, took 0.7kg of gear, which included his phone, GPS watch, and camera.
