British astronaut Tim Peake ran a marathon in solidarity with runners in London on Sunday - just 250 miles above them.
He took part in the challenge with the help of a special space-proof treadmill, and used a harness system to actually stay in place on it, tracking his progress through London's streets with the help of an iPad.
If a marathon wasn't already a gruelling enough physical challenge, turns out in space it's even harder. Sustained exposure to microgravity wastes astronauts' muscles and thins their bones - which makes keeping fit and healthy really difficult.
Tim finished the 26-mile race with an estimated time of 3:35:21, according to the European Space Agency. He's run the London Marathon once before, in 1999, with an impressive time of 3:18:50, and was aiming for a new time of under four hours.
As part of his six-month stay aboard the International Space Station Tim has been conducting experiments which will hopefully help researchers on earth better understand the effects of muscle wastage and osteoporosis.