Answer: The International Space Station

In 2008, Richard Garriott–British game designer, entrepreneur, and space enthusiast–visited the International Space Station as a self-funded tourist brought aboard by a Russian delivery rocket. While he was there, he established Earth’s most remote geocache–a cache sought by those who engage in the sport of finding and recording containers hidden all over the world that contain tokens and notes from other travelers.

Garriott explained the location and composition of his cache to Geocache.com, the world’s largest hub of geocaching information:

I traveled to the ISS on October 12, 2008 becoming the first second generation astronaut. While there I created this geocache aboard the Russian Segment of the ISS. The cache itself is locker #218 as shown in the provided photograph. There is no logbook in this cache, out of respect for the Russian segment of the ISS, and the fact that it would be a fire hazard to include one in this locker. You will find, however, that I attached a Travel Bug to the locker. I am hopeful that any future geocaching astronauts will start my Travel Bug on its way home, and leave one of their own in its place to start a similar journey.

While the location and lack of log book are a tad unconventional, it’s certainly an interesting place to stash a cache–maybe a young geocacher will be inspired to reach beyond the bounds of Earth just to continue the tradition of leaving hidden treasures in space.