To reveal the details and topography of the whole Altus Plateau region, you'll need to find three Map Fragments at the Steles located in the Altus Plateau proper, Mt Gelmir, and the Capital Outskirts.

Mt. Gelmir is a large mountainous region with an active volcano and rivers of lava in Elden Ring. This is one of the main regions that you have to explore to beat the game. Mt. Gelmir is actually a ...