Originally posted by Juggernog
For the people that think that this is just a imaging error or faked or whatever, you need to recall the huge hole they found on mars.
The mysterious dark spot you see above in the MRO imaging is speculated to be a dark hole in the Mars terrain that is so large and deep that very little light is reflected back out of it. It is suppose to be about the length of a football field across which would roughly be about 100 yards. It is actually just one of seven such pits or holes discovered in the Themis imaging and they are known collectively as the "Seven Sisters" and this site is the smaller of those They are all named and this one in the MRO imaging is named "Jeanne."
Thank you for posting this, I'd never heard of it before and was amazed to see it confirmed by several other sources.
Wonder if these guys have anything to do with them: