Even though Mars is a small solid planet, it has so much big potential.
https://solarsystem.nasa.gov/planets/mars/overview
https://en.wikipedia.org/wiki/Mars#Internal_structure , https://www.youtube.com/watch?v=kca3Y8XUK1c
https://www.cnet.com/news/in-historic-first-nasa-spacecraft-maps-what-lurks-below-surface-of-mars/
https://www.nationalgeographic.com/science/article/mars-1
https://en.wikipedia.org/wiki/Mars#Holes
https://www.bbc.com/news/science-environment-57935742
https://en.wikipedia.org/wiki/Mars#Future
https://www.independent.co.uk/news/world/americas/elon-musk-mars-scientist-braun-b1879535.html
https://www.spacex.com/human-spaceflight/mars