Been on the server 30 minutes, explored more than I've built since I first bought the game.. just one question for now.. Whats the Sacrifice Room for in the Cathedral?

Hey all, I'm Fast. I'm a long time gamer and have been playing Minecraft for a few months now - generally that means logging on, digging a big hole, building a small house and dying to roaming packs of creepers. I've only recently become aware of Minetown, and after several days staring avidly at the worldmap.. I love the giant mooshroom.. and the giant Bender.. the star destroyer.. or all the hordes of little towns. Its just.. so big. And yet I feel like I'd like to add my own legacy to that map. But I'm so confused by all the rules and the regions/towns/protection .. its all far too complicated for me. But if you don't mind, for the moment I would just like to be a tourist, and see the sights first. Well I hope to see some of you in game soon.. and I'm looking forward to seeing some of these creations close up.