Alien hunters regularly find what they claim is evidence of ancient statues and ruins on Mars in Nasa images taken by its rovers and space probes.
There is also a well established conspiracy theory that this alleged alien civilisation was wiped out by a nuclear war that destroyed the atmosphere of the planet.
But, space experts have spent decades studying the surface of the Red Planet, but there has so far been no firm proof of any life ever evolving there, let alone intelligent forms like humans.
And, NASA, and other experts deny finding any evidence of even the most simplistic lifeforms yet on Mars, despite sending various rovers and space probes to explore the Martian surface.
However, new scientific research could have explained what did happen to life on Mars, if, indeed it ever existed.
New research says mega tsunamis caused by an asteroid strike would have engulfed the planet with water in an extinction level event.
A team of scientists has found what they think is evidence of a tsunami impact crater which could be a game changer in the history of Mars.
Nasa has already said it has found evidence Mars was once covered with oceans much like Earth.
The tsunami is thought to have been so powerful, it would have wiped out any trace of life on the planet, ifit had existed at the time.
Geophysics professor Francois Costard said: “We found typical tsunami deposits along the dichotomy between the northern hemisphere and southern hemisphere of Mars.
“It supports that there was, at that time, a northern ocean.”
The main theoretical reason for the tsunami occurring would have been an asteroid hitting the planet.
When a large asteroid hits water, it can create two tsunamis when it hits the ocean surface and the ocean floor.
The crater, and the thumbprint formation at the site are proof of the ancient tsunamis, the researchers claim.
Professor Costard, study lead, added: “The possibility that a large ocean once occupied the Martian northern plains is one of the most important and controversial hypotheses to have originated for the exploration of Mars.”
Although the team did not comment on whether any lifeforms may have existed at the time.
Last year NASA revealed that Mars had lost nearly all of its atmosphere, making it inhospitable now, after the sun stripped it away with solar rays over billions of years.