Sanctuary (UO)

The Sanctuary is a small settlement of elves exiled from Heartwood in the Britannia of Ultima Online, located at 00°58'N 37°03'W near one entrance of the Solen Hive.

Description
The grove however can only be reached through a cave system that is filled with monsters fighting each other constantly, but who'll turn on any intruder at once. They concentrate on a war zone in the center of the caves. Therefore only battle-hardened adventurers can ever hope to reach the settlement - which welcomes even the worst criminal - and where several interesting missions await.

Care has to be taken not to fall into one of the holes strewn throughout the cave, as they lead into a deeper level filled with horrible traps, that has only one hard to reach exit.

Trivia

 * There are several subdivided regions of this dungeon that are entered by crossing a threshold. These thresholds act like server lines - meaning the monsters do not (often) cross from one area to another. However, unlike server lines, it is possible to cast EV or Nature's Fury across boundaries. You cannot loot across the threshold, and it is often suicidal to step across and try to claim your booty.
 * Three different bosses can be found in the dungeon.