An international crew of researchers emerged from a windowless space module in Moscow on Friday.
They took part in an experiment to simulate the long flight to Mars.
French researcher Romain Charles was pale but smiling: "After 520 days of motionless trip, we are proud today to prove that humans can go to Mars."
They didn't actually go to Mars but did you know that the first known map of Mars dates back to around 1840?
That's when two German astronomers made drawings of the surface of the red planet based on years of telescope observations.
So here's the question: Where was their observatory?
Today this spot is inside Berlin's biggest park.
Answer: the Tiergarten. Back in the 1830"²s it was where German astronomers peered at Mars through their telescope and drew the first ever maps of Mars.