Now, it's hard for me to put in the right words exactly what I'm thinking, but I'll try.

Imagine an advanced civilization on Mars, not much more advanced then our current one. What problems do we face? Overpopulation, war, global warming. All serious threats that iff we don't figure out soon could end life as we know it.

100 years from now we are planning to have humans living on mars. Now, what if the rolls were switched. What if humans sent a manned mission to earth 200,000 (not actual time just an example) years ago because their planet was dying? What type of knowledge would they be able to carry with them?

Say they sent 15 people, surely 15 people couldn't carry enough knowledge or technology to rebuild and start right where they left off. It would take thousands of years, trial and error to re-learn all the lost information. Is it possible that while this manned mission to earth was happening a catastrophic event took place on mars that wiped them out? Would this information of our origins survive thousands of years of war, natural disasters and other things that early explorers would face?

I think it's highly likely we will find proof of an advanced civilization that once lived on mars.
Sorry if this is hard to understand. I just feel like there is a huge possibility that something like this happened.