Dungeons in Rappelz are ownable by player guilds. There are two copies of each dungeon. The entrances are always near each other.

Dungeon owners can set a tax rate for their dungeon. The tax rate can go up to 10%. The tax is automatically levied against all Rupee and Lak drops in the dungeon.
This can make dungeon ownership very lucrative.

Players may enter dungeons at any time to explore normally. Players in Guilds may take part in dungeon Raids and Dungeon Sieges at specific times during the week.
Raids and Sieges both require the guild leader and a large number of guild members.

Guilds may control only one dungeon at a time. Guilds cannot Time Attack if they own a dungeon. Guilds can only apply for a Time Attack on one dungeon per week.