In 2007, researchers were scouring over satellite imagery of the remote Canadian wilderness on Google Earth when they spotted something incredible - a beaver dam so massive, it is visible from space. Measuring in at some 2,790 feet in length, the enormous structure even rivals many of humanity's most impressive creations.
Among those who heard reports about the discovery was Rob Mark, a modern-day explorer who was eager to embark on a challenging new adventure.
"I read an article about it and was fascinated that something was that big. Then I read couple of other articles about it and there were two recurring themes: one was that it's incredibly remote and very difficult to get to, and the second was that no one has ever been there," Mark tells The Dodo.
"Those two things met my criteria, so I started doing my research on what it was going to take get there."
After plotting a rough course that would take him through some of the most impassible terrain on the planet, Mark packed his gear and traveled to Fort Chipewyan in northern Alberta, Canada, the last outpost before his 120 mile trek to the dam.
It took him nearly five days to arrive, bushwhacking through the untraversed landscape, inching closer to the beavers' hidden fortress.
"This was the toughest bit of journey I've ever been on. The land is flat, but the vegetation is so incredibly thick. Then you're walking through muskeg and that turns into bog, then out and out swamp," he says.
The last mile stretch before the dam was so boggy, Mark says it took him five hours to pass through, but the effort was all made worth it when he first laid his eyes on the beaver's creation.