It's possible some previous civilization developed here on Earth and then was wiped out, but: they must have been wankers.
SpaceX is aiming to be on Mars by 2024. The hope is to have colonies shortly thereafter, and a city by 2050.
https://www.inverse.com/article/5129...rting-a-colony
And Elon Musk's predictions have always been right. (But his timing has always been way too optimistic.)