Making rope is hard. Making rope the way the Vikings did it over a thousand years ago is even harder. First, you have to find the right tree. Then, you have to strip the bark of the tree when the sap is rising. And then, you soak the bark you just harvested in the sea for three to four months before you can even think about turning it into rope.

After all that soaking in water, the layers are all split up become much more malleable and, I guess, rope ready. Norwegian filmmaker S Ensby writes:

Rope maker Sarah Sjøgreen lays the bast rope, and makes a traditional carrying rope with three strands, for transporting the cut grass during hay making season. The bast is naturally water proof, and rots very slowly compared to other rope materials. This explains why it has been found intact in viking excavations dating back to the 800s.

Watch the full, insane process: