The sanity of Elon Musk, CEO of Tesla, could very well be questioned.In the good sense of the word, of course.A few months ago he announced that he would sell all his mansions to give himself body, soul and pocket to the race to conquer Mars.Many did not believe him until he went to live in a 40-square-meter prefabricated house on the launch site of his company SpaceX."It can't be, he will keep at least one of his mansions, in case he gets into the luxurious vein," he said to himself then.Nothing could be further from the truth, because the tycoon has just got rid of his last property, located in Hillsborough, California.The mansion, with a stately court and which receives the name of Guignécourt (in honor of its first owner at the beginning of the 20th century), is spread over 1,486 square meters and has the best facilities.We have a dozen bedrooms, nine bathrooms, a large living room, a library with a fireplace, a huge kitchenette, a dining room, a music room and a media room.In addition, Musk recently renovated it to enable several spaces that would serve as a dance and cocktail lounge, since for a time the mansion was used for organizing events.The billionaire bought it in 2017 for 23.3 million dollars and today he sells it for 32. In total, he has entered about 100 million for all his properties.In this way, he focuses on the increasingly common business race to become "owner" of the space.Let us remember that Musk has long dreamed of colonizing the red planet to such an extent that, as you will see, he has become almost an obsession.A few months ago, the tycoon openly stated in a conversation with Peter Diamantidis, creator of the XPrize Foundation, that “going to Mars is dangerous and uncomfortable.It's a long trip.Also, you may not come back alive, but it's a glorious adventure and an amazing experience, although I think a lot of people will die at the beginning."