Some amateur astronomers have spotted what appear to be clouds in the Martian atmosphere--unfortunately, in 2012, but I just saw the news on it this morning--of a size and shape that baffles scientists and may force us to re-examine our conceptions about the Red Planet.

http://www.msn.com/en-us/weather/topstories/cloud-over-mars-leaves-scientists-baffled/ar-BBhDPiw?ocid=mailsignout