At this point which one is more believable Atlantis or Life on Mars ?

Life on Mars

The Aquaman movie was just that. A movie.

Edit: unless we’re talking about the actual lost city of Atlantis, and not some fan fic advanced civilization.

Atlantis.

Atlantis

But not with sentient occupants

Depends on how loosely we're defining "Atlantis." If we're simply talking about a very old city that just so happened to get caught in a flood, then yes, it's very possible that it exists.

If we're talking about an undersea utopian society ruled by Jason Momoa, then definitely life on Mars.

Life on mars considering the difference in complexity of life we are talking about.

R'yleh

Atlantis.

I think both are fact. Nobody thought Troy, Sodom and Gomorrah, Machu Picchu or Dwarka actually existed but they were found & we've been finding lost civilizations nobodies even heard of before for centuries. Atlantis is definitely out there.

Life on Mars.

The actual city Atlantis? Yeah, I believe it existed.

Atlantis

Mars. We always believed that aliens are really advanced and may have tech which is able to hide them from us. Atlantis,well I can believe the city exists down there, but I can't imagine people living there.

The one that actually has some scientific evidence for past life in the distant past.

On that note, I'm open to the idea of Atlantis. We've found tons of submerge ancient civilizations of towns and temples off the coast of Asia in the Pacific ocean. I wouldn't be surprised if we one day find Atlantis and it was a city that become submerged under the ocean.