Altars are primarily used to [[praying|pray]] at to gain [[Faith]].
Another use of altars is [[sacrificing]].
=== Domain ===
Altars also create the domain of the gods. You know when you're in such a domain when you get the message "You feel the presence of <god>".
The Domain with the greatest "power" takes effect, and only 1 domain can be in an area.
The "power" and size of a domain is controlled by the quality of the altar, for example a 10ql golden altar will have 18 tiles radius, 50ql - 57 tiles, 90ql - about 96 tiles, a stone altar of 21.97ql has 24 tiles radius. The domain seems to get weaker the further it is from the altar and might get overpowered by another god's domain.
It should also be noted that a few altars are still "bugged" as they were made before the recent domain changes. (5 June 2012 - [http://wurmonline.tumblr.com/post/24462560831/faith-zone-changes-achievement-bugfix faith-zone-changes-achievement-bugfix]).
Domains get updated approximately 5 minutes after a server is restarted, so for a small period of time after a restart, there are no domains. A new altar's domain can take around 5 minutes to update, and a domain change can take up to 10 minutes.
Underground altars will still give their bonuses above ground. For example, underground [[Libila]] altars will spawn mycelium above ground. However, you will not receive the domain message moving through these underground altars.
==Notes==
* The material type of alter does NOT affect domain range. A quality 10 wooden alter will have the same range as a quality 10 golden alter.
=== Creation ===
If you are trying to make an altar for a Priest of a different religion, i.e. you are a black lighter and your priest is Vynora, you can build the altar, and have your priest put the last piece of the altar on by unclicking faithful and attaching the last piece. Works for wooden and stone altars.
=== Destroying an altar ===
If you desecrate an altar of your deity you stop following that god and have your faith and favor reset to 0. [[Exorcism]] xp is gained. The altar is removed from the game.