There's not much of a "mystery" to this one!
Just complete the A Tour of Iconic Athens!! adventure labs! In addition to getting to see some of the sights in one of my most-favorite cities, at the final stop, you'll get the coordiantes amd a hint for this cache! That's it!
Easy-peasy, nice and breezy!!!
The difficulty rating is for completing the labs. The hide itself is about a 2...
Note: This one may be tricky on game days...