Mars Was Once Wet
It may be hard to imagine today, looking at the dry, red surface, but Mars was once a warm, wet place similar to Earth. Recently evidence has been found that indicates there may still be frozen lakes located underneath the poles. There is also evidence that the northern hemisphere used to be one large ocean, but the water dried up thousands, if not millions, of years ago.
Other Suspected Aliens Have Been Found Before
There have been people to make the same claim in the past as well as remains that have been found. Both of these show evidence of being not entirely human. Some have been dismissed as simple deformations in earlier humans, while others are still unexplained. Whether you choose to believe that these specimens are alien is up to you, but they certainly don’t look human.