Article written by: Gary [USMA77]

The “Your Statistics” tab in Geocaching.com identifies this cache ‘type’ as UNKNOWN Caches.  Project-GC stats labels them as MYSTERY Caches.  Geocaching.com defines MYSTERY Caches as follows:

“Also called a ‘puzzle cache’, players might need to solve a puzzle or bring a special tool to reveal the next waypoint or final coordinates.  Most often, the final container is not at the posted coordinates which is noted in the cache description.”

But Mystery/Unknown/Puzzle Caches can be so much more.  Here are some of the ways this ‘type’ of cache is used along the geocaching trail.

• Puzzles solved at home: Some final coordinates can be solved from home with puzzles located somewhere on the cache’s webpage (page).  Everything needed can be found on the cache page, or starts from the cache page.  The puzzle can be in plain view or hidden on the cache page.  Easy or difficult.  Maybe something stands out on the cache page as odd or unusual? 
• Field puzzles: To determine final coordinates for other puzzles, the geocacher must go to the posted coordinates and perform task(s) identified in the cache description.  The required task(s) on site can cover a wide range — answer questions about local objects/subjects that will lead to the final coordinates (maybe through a GeoChecker or other online tool), or solve field puzzles including gadget caches that reveal the cache container.  Look for the “Field puzzle” attribute on the cache page.
• Adventure Lab Bonus: Another use of Mystery/Unknown Caches is “Bonus Caches” related to Adventure Labs.  Solving a 5-stage or 10-stage Adventure Lab can reveal the coordinates for a nearby “Bonus Cache”.  Look for the “Bonus cache” attribute on the cache page.
• Series Bonus: Mystery/Unknown “Bonus Caches” can also be tied to a group of caches with a common theme that rewards the geocacher with coordinates to a “Bonus Cache” obtained from pieces of information found in the themed caches.  Look for the “Bonus cache” attribute on the cache page.
• Challenge Caches: Mystery/Unknown ‘type’ caches are also used for “Challenge Caches”.  “Challenge Caches” are generally found at their posted coordinates, but in addition to signing the paper log at ground zero, the geocacher must meet the challenge requirements detailed in the description before they can log a SMILIE and show the cache as found.  Look for the “Challenge cache” attribute and a link to Project-GC’s Challenge Checker on the cache page.  Most “Challenge Caches” are registered in Project-GC’s Challenge Checker tool and can tell geocachers whether or not they qualify for that challenge.  Even if a cache page does not contain a link to the Challenge Checker tool, it may still be registered, so check.

Other cache ‘types’ have just one defined use.  With all these uses for Mystery/Unknown/Puzzle ‘type’ caches, hopefully more geocachers will stop avoiding them and start placing and hunting them.