This isn't simply a list of "Unknown" Cache types in Manhattan. This is a list filtered for true puzzles that require good problem-solving chops (as opposed to other excellent Unknown Caches which require more task completion or information gathering). Lovers of the "Aha!" moment should enjoy these.
Difficulty for established caches is crudely estimated by calculating the average number of days between finds. (Obviously this is not a perfect measure, but bear with me.)
Difficulty ratings last updated May 2011.
If you manage to find at least 15 (or 30!) caches on this list, you may qualify for a special, limited edition Dastardly Pathtag! See this thread for more information: (visit link)
About Bookmark Lists
A bookmark list is a user defined collection of listings. They can be used as to
do lists, watch lists, a way to organize listings you find, or whatever you decide.
You can keep them private or share them with others.
Bookmarks can be added on the page for the listing or on this page using the waypoint
Bookmark names may be different than the actual listing. Click on the listings to
see the actual names.