The "Challenge of the Century" caches which are becoming popular in
most states, require that a cacher has found at least 100 of a
certain type of caches in order to log the challenge cache as
found.
This cache, The "Challenge of the Millennium" requires that the
cacher has found at least 1,000 of a specific type of cache, other
then "Traditional Cache," the good news is you can choose which
cache type to use.