Geocaching is like a very large (world wide) treasure hunt. containers ranging from micro caches (very small) to macro caches (very large plastic buckets) all over the world. Each of these caches holds some sort of "treasure". The fun comes from both the traveling to the cache and then trying to find the cache once you are at the location. Once you have found a cache, you can log your find into the log book and trade something out of the cache for something they have brought with them.you could leave (L) a rubber duck (T) a figurine.