If humanity discovered evidence of alien life on Mars, could we really trust our eyes? From NASA rovers to soviet orbiters, the red planet has seen a number of visitors in the last decades. They could have potentially transported durable microorganisms from Earth to the surface of Mars. This introduces us the field of astrobiology and the search for life outside of Earth. Where is the best place to look for this kind of life, past or present? Most likely, the answer is Mars.