Yesterday in Eve Online; in the system of M-OEE8, over 5,700 pilots participated in the destruction of the first fully armed Keepstar. The siege lasted over 7 hours with over 237,000 ships destroyed over the duration of the battle. The Keepstar is the most expensive structure that players can build in Eve, requiring months and months of time and effort to gather resources and construct components.
PC Gamer did a nice write up of the battle and the events leading up to the destruction of the Keepstar.
Also included with the write up is a segment of the twitch stream showing the final moments of the Keepstar with an explosion that would put a tear in Michael Bay's eye.
http://www.pcgamer.com/watch-as-over-5000-eve-online-pilots-destroy-a-fully-operational-death-star/