What are the pyramids and faces and tunnels found on mars
if there are ETs why we cant see them.

Maybe they live underground.

It has been shown that the great face on Mars does in fact not resemble much of a face at all. Early images of the Red Planet did not show much detail resulting in a distorted, fuzzy type picture. Thus one area of the surface happened to resemble a human (or something like human) face. Later on as technology advanced and more detailed images were taken, the great face began to look less and less like what its name suggests. The pyramids are a different story. Mars is significantly smaller than the Earth so this provides for less gravity. Those mountain ranges dont have as much gravity to fight as they would on Earth, so mountains on Mars can easily tower over Mt. Everest and then some. Throughout the surface of the planet, inconsistent bulges may appear like pyramids or mountains or whatever you wish to call them. Mars is indeed a prime candidate for extra terrestrial life and shows some solid evidence of once supporting liquid water. Life may infact still be on Mars on a molecular level, however intelligent life that we may be able to communicate with seems to be a chance of considerably less than a googolplex to one.

Maybe if ud melt mars polar ice caps mars would be flooded with water

We can't see them because they are long dead and the cities are buried beneath a deep layer of perma frost and dust.

around 41K yrs ago, a galactic core explosion triggered vast chain reactions in the solar system. Mars had already been devastated by another such event that occurred during Earth's Permian era. MArs had no rotating core to stabilize its magnetic field so the Permian event greatly weakened and damaged its mag field and the next event destroyed it. The people on Mars may have genetically seeded this planet with their species (combined with local DNA so that survival and evolution would not reveal the rift) during the Permian, this explains the rise of mammal like lizards. Before that Earth seems to have been evolving toward dinos and the dominant species today might have come from veloci-raptor like creatures instead of mammals if the planet had been left to its own devices.

when the next event finally killed Mars as a living world, the Martians came here and started civilization again. This accounts for civ appearing as if out of no where.

the ones that came here are now us but another group may have left this system and are now, what we call, aliens, revisiting their long lost brethren.

I'm not sure these long lost cousins are exactly nice though, which accounts for why the abducted are so afraid of them.

nuts huh?
Dawn

Painkiller 24 explained it perfectly.

and melting the polar ice caps on mars to flood mars with water wouldn't do much since it would just freeze again, Mars tempature range from +25 to -140 degrees.