“The task of exploring is daunting but exhilarating,” says Graham. “Unravelling the mystery of what is around the corner. Why is the rock like that? It’s a combination of time travel, a geology field trip, climbing a mountain peak, and camping in the rain, all so we can dive and uncover the secrets the mountain is holding.”

And the mystery remains: after reaching the deepest point ever attained by cavers in Canada, the underwater passage went deeper, beyond the team’s reach. Divers Graham and teammate Matteo Bucalossi reached the limit of the six air cylinders that were hauled down to the sump, and going deeper will require a new plan to support longer dives and deeper exploration.

The expedition’s questions also extend beyond the next unexplored passage. University of Toronto researchers will analyze mineral samples to investigate the age of the deepest known passages, and water samples destined for the University of Montreal will support research into cave microbes and the communities they form. Hundreds of thousands of years of Earth’s climate history are locked into cave mineral formations, while the extreme microorganisms have potential for medical breakthroughs, biomaterials, and astrobiology.

This year’s journey builds on past trips to the karst environment which were featured in the award-winning documentary Subterranean, adding another chapter to the already record-breaking cave. However, neither the map nor the science is complete. Samples still need analysis, and newly documented passages leave further routes to investigate.

As Stenner puts it, “The results are a record of what we’ve learned so far, not the limit of what is there. There’s so much more to discover.”