Hello there and welcome to MY challenge. This is a Mystery Challenge that requires you to have found at least 555 Mystery Caches. If you use the checker below you can see if you qualify. The checker is for your Puzzle Caches. I feel that the amount of time it takes you to qualify for this challenge will make the Difficulty rating a 5.
Challenge Checker
You can physically log this one but until the checker works for you please don't log the smiley. I had such an adventure qualifying for this one that I wish you the best in your quest. I also want to thank all the COs for their caches that I used to complete this MILESTONE!!!!
Congratulation to HjatHome for a FTF!!!!
Eyeash