Mega-event cache
From Cacheopedia
A Mega Event Cache is a type of annual event cache that holds at least 500 participants (e.g. GeoWoodstock). The pages of a Mega Event mark the location, date, time, description, requirements, etc. of a geocaching event, just as in the case of a regular event cache. For paticpating in a Mega Event, a geocacher is able to log and receive a Mega Event icon to add to their cache counter.
