Seattle was a short-lived world that existed on the server. Its sole purpose was to be a purely survival World. No spawning items, no nothing. Users had to mine things and craft things to survive. Monsters were everywhere.
The reason this didn't last long is that Lostwave couldn't figure out how to block people from just getting items from the store and bringing them. Kind of defeated the purpose. Much later plugins have matured and there is a way to block this issue and it has come up a few times to re-create a Survival only world. This still hasn't happened though.