Travelling through the forests of northern Scandinavia, one can often encounter characteristic X marks carved into trees.

Some shoot out of the soft rock like reptiles bathing in the sun. Others are mysterious depressions resembling an ancient board game played all over the world. And a few are straight-up puzzling.

For many, the sculptures' mysterious carvings of animals and symbols are impressive as they ... bringing out in vivid colours their carved salmon, ravens, wolves, boars and even a battle scene.

The discovery, which includes more than 20 ritual protection symbols carved into its walls, was made by Rick Berry, a long-time volunteer at English Heritage. Over the course of two years ...