I started geocaching as a hobby in 2013. Since then, I have found more than 1000 caches across 18 US states as well as in China. During these years, I stepped out my comfort zone several times, and became a more experienced geocacher.
Geocaches come with different types. Traditional is the most common type: the webpage of a Traditional cache has its coordinates, and I can straightforwardly find the physical container at that location. Another common type is a Multi: I need to visit a location, collect information such as reading text from a plague or counting the number of windows, and then find the physical container at a different location whose waypoint is computed from the answers from the first location. I'm quite familiar with these types.
One geocache type I'm uncomfortable with is Mystery puzzle cache. These caches are published with bogus published coordinates, but the webpage contains clues to find the real coordinates of the physical container. The puzzle could be a piece of cipher text, a crossword puzzle, a strange picture, or something else. Although I know a thing or two about classic ciphers, I could not get a hold of them.
This all changed when Geocaching HQ assigned me a mission to find a puzzle cache in August 2014: