The World is Our Playground is a well-known geocaching motto. I didn’t know but there is also a song with this title, not related to geocaching even though the second verse matches quite well what we do:
There's always a new place to go,
There’s always an adventure waiting,
There's always a new plan to make.
The first verse though seems to better describe the box’s location.
There’s always a new friend to make,
There’s always a space at the table,
There’s always a new game to play.
The box’s location is a playground too, but for a different kind of games, and lately became the meeting place for the local geocaching community and events venue. And what a geocaching HQ is without a geocache, right? Hence this letterbox 
The box looks sturdy but it’s also delicate, please handle it with care. The stamp should remain in the box, it is not swag. Please put everything back in reverse order paying attention to details.
PS The location is open Wed - Fri 18 - 24/ Sat- Sun 14 - 24. No purchase is necessary to log this box, just ask for it.