Puzzle cache
From GeoWiki
A Puzzle Cache is a Geocache which requires the Geocacher to solve a puzzle in order to find the Geocache.
Puzzle Caches are often known as Mystery Caches.
Puzzles vary from the simple to absolutely diabolical. Difficult puzzle caches can take weeks to solve.
007 is an example of a Mystery Cache in Adelaide.
i!8: Get Smart now archived, but reputed to be one of the hardest puzzle caches in Australia.