美国拉什莫尔山上空的乳状云
2020年12月07日 Mammatus Clouds over Mount Rushmore Image Credit & Copyright: Laure Mattuzzi Explanation: What’s that below those strange clouds? Presidents. If you look closely, you may recognize the heads of four former US Presidents carved into famous Mount Rushmore in South Dakota, USA. More obvious in the featured image are the unusual mammatus c...