"I’m going to talk to you about a wonderful kingdom. Although many disagree, there are and always will be wonderful kingdoms in this world..."
Miguel Torga, Um Reino Maravilhoso,1941
It's a cache, a decent size one, log your visit while contemplating the wildlife around you. Down below, the Azibo lake will be the only witness!
Find it, log it, take some photos (or don't), takeyour time, don't rush, trade something, leave a travel bug if you want, just don't destroy anything, for it was there long before you arrived.
Don't take The Wondeful Kingdom for granted, there aren't much more...