This is NOT a challenge cache. Anyone is welcome to come find it and sign the log. The container is at the published coordinates.
However, there is an optional task for those of you who share my interest in seeking out long-forgotten caches, as detailed in my "Forgotten Years" series: Five Forgotten Years, Fifteen Forgotten Years and Fifty Forgotten Years.
If those kinds of caches interest you, and you happen to have over 100 years of accumulated unfound time, AND over 100 qualifying caches, then I invite you to brag about it here in your log. Let us know how many qualifying caches you have and how much unfound time you have.
However, as mentioned earlier, this is entirely optional! For some back-story, after the 50 year challenge was published, there was a long period where Groundspeak were not accepting lonely cache challenges because no automatic checker worked for them, and an automatic checker is a requirement of challenge caches. Since then some checkers have become available (thanks GreyHams) but it seems we still can't publish new lonely cache challenges because they are considered competitions against other cachers instead of individual achievements. However I only learned this after placing this physical container. So, this cache is now a simple traditional with an optional task for people who feel so inclined.
Enjoy!