Mars has high radiation, low gravity, almost no air, and poisonous soil, making it a hazardous place for humans.

“of impact and i say well you know if we take musk at his word the good news for him is it's really easy to die on mars um because mars is a really horrifying place uh there's um you know the radiation levels are too high the gravity is too low there's basically no air and the dirt is made of poison um and yet”