There are not buildings on Mars. But that doesn't mean we can't pretend there are by drawing squares around conveniently shaped rocks and giving them a "97%" chance of being evidence of alien civilisations!
Everyone's favourite hyper-optimistic UFO website suggests the buildings
"over millions of years in space, they get covered by cosmic dust particles and get buried". That's why they look so much like, you know, rocks.
The site adds, confusingly, "it doesn't get more intestine than studying a ancient culture on another world."
Still, it makes for a good distraction from the actual, mind-bending fact that we are entirely alone in the volume of space that we will ever manage to travel across, and that ultimately we have to survive on our own, here, or perish.
Have a great day everyone!