Watch this group of French mountain bikers ride down an abandoned salt mine illuminated solely by rather modest looking headlamps.

The group was headed up by a Killan Bron. A quick Google reveals that Bron has a history of similarly daredevil and high-concept ideas for mountain bike films and photos.

Apparently Bron and his co-nutter Maxime Peythieu found these tunnels three years and they’ve been plotting a return ever since.

>>> Watch Marcelo Gutierrez ride in an underground cathedral

Although the footage looks like the mountain bike lights they’re using aren’t that powerful it’s more likely that they are but it’s the GoPro 5 that can’t quite deal with the darkness.

With the lmaps turned off, Peythieu describes the conditions as “the most intense black I have ever seen!”. We’re not sure “seen” is the really the right word but you get the idea.

The total time the crew spent down in the maze of tunnels was four hours. Rather them than us!

Bron’s words of caution: “We remind our readers that, although old, these mines remain unstable. That is why we will not disclose their exact location. According to the premises, these former mine galleries may collapse at any time. We strongly advise against going there.”