Unfortunately, unambiguous signs of life off Earth have not been found yet, but we are doing our best! We already have a lot of valuable information on how the environments look like in other Solar System bodies AND, (not) surprisingly, that they have counterparts on Earth! However, are they hospitable enough? Or, as we astrobiologists say, are they habitable? This question leads us to the idea that understanding how life can thrive at the most extreme terrestrial environments, and how we can study it, will give us clear clues on how life could be possible outside our planet. If you want to find out about the almost philosophical question, “Are we alone?”, do not miss this talk by Dr. Miguel Ángel Fernández.