the world's highest junkyard

Most climbers going for the summit have a camp at the South Col. When stumbling down from their sometimes successful, sometimes not, summit attempts, they don't feel like picking up their tents, oxygen canisters, toilet paper and whatever they've managed to drag up there. At 14,000 feet it takes 40 years for toilet paper to decompose. At South Col's 26,000+ feet, nothing does.

Every year nowadays, there at least one cleanup expedition trying to at least clean what's been left the very same year.

One might make a similar claim for various Earth orbits, especially the geosynchronous orbital ring, since there's lots of old satellites and parts of satellites (and assorted other junk from space missions) floating around up there. In fact, there are some concerns that all that debris might damage important equipment up there.

On the other hand, it could be argued that these orbits are not technically "in the world" at all, in the sense of being on Earth.