RE: Rock Cairns

Officially they are trail markers for navigational purposes

Correct, which is why you SHOULDN'T MAKE THEM. Because you're messing with the trail markers.

Also the word for them in Inuktitut is Inukshuk. And they are still used up in Nunavut as markers. They are actually much more than markers up here, they're equivalent to town signs that tell you "fish here" or "caribou travel through this area" sometimes even "Sea ice is dangerous here, stick to the land"