: Satellite photograph of a plain with several lakes and distinct rounded features, labeled ‘A,’ ‘B,’ or ‘C.’

"A"s mark old thaw lakes that drained and permafrost re-formed (note the polygons), resulting in a pingo in the center. "B" marks a recently drained thaw lake; it drained to the southwest into the bigger lake, but only partly so some water is still left. "C" marks remnant yedoma.