It's the farthest distance you can travel without leaving the planet.
It’s just over 20,000 kilometers (about 12,500 miles) to the exact other side of the earth from where you are right this second.
Or, if you travel straight through the earth, it's around 12,800km (or about 8,000 miles) to your antipode.
That's farther than any single "Point-A-to-Point-B" journey on the planet!
A small handful of astronauts are the only apes among us – in all of ape history! – to have ever been further than 20,000km from where they were born.
We, the humans of 2019, are probably the last generation of non-spacefaring humanity. Our children will likely explore space, and our grandchildren almost certainly will... but until someone is willing to build and sell us cheap personal spaceships, we're all trapped here.
(Looking at you, Elon Musk!)
IN FACT, most of the people that go to space only go as far as low Earth orbit (LEO). The International Space Station is only 408km (254 miles) away from the surface of the Earth – that’s less than the distance from San Francisco to Los Angeles!