Violent impact on Mars left billions of craters - and an important clue. The 14 kilometer wide Corinto crater is likely to be the youngest giant crater.
Scientists believe that asteroids large enough to create a crater of this size only hit Mars every three million years. The impact also created numerous smaller craters in the surrounding area. This leads researchers to believe that the Mars region was covered in water or water ice when it was hit about 2.3 million years ago. The results could change the view of Mars' past.