If you don’t walk it, it will disappear. That would be like letting the ancient romanesque cathedrals of Europe fall into ruins and be carted away as bricks. That’s what you’re looking at, so get on out there!
Both are heads. Literally. The word remains in English as a cob, known in cobblestones (each has a round head) or a cape, which is also a headland, and that’s the Icelandic word: hæð, or head, or height. Remember that for the culture that settled this magical place, these really were heads. And so they remain.