As the banner says, if you qualify, you can log it. All OCNA Challenge caches are locationless type, arranged as Geo-Art in The Gulf of Mexico.They are all "unknown" (?) caches, owned by a special Admin account, OCNAChallenges. Do you have an idea for one? Feel free to contact us.
I get around (Finder level 4): There are 50 United States, 31 Mexican States, 10 Canadian Provinces and 3 Canadian Territories. Additionally we will count Washington, District of Columbia and The Mexico City Federal District. That adds up to 96. Your task is to find OCNA caches in any 25 of them.
Verification: Please post your qualifying finds with your log, preferably in the http://coord.eu/OUXXXX format, and also keep in mind you can link to cache pages using our cache log editor, although is not mandatory. To see if you qualify, you can just look through your list of finds in your profile, but keep in mind, we do have the equivalent of a Groundspeak "my finds pocket query", (instructions here) and that .gpx file is easily imported into GSAK, or any similar stats program. We recommend a "gpx gc" file, and we also recommend GeoGet as a free alternative to GSAK, should you not be a paid full version user of GSAK.