In Assassin's Creed Valhalla you can come across Cairns that will give you extra points. On this page of our guide, you will find out where to find Cairn locations in Sciropescire.
You will find the cairn in the south of Lake Dudmaston.
It is not an easy task. You have to arrange them so that they go upright. This way you will reach the determined height. Move the stones so that they lean on each other and won't fall.
This will give you an extra skill point.