data structure for dungeons

[Sofus Macskassy]

I am trying to build up a 3d dungeon, but can't figure out
what kind of data structure to use.  I don't want to use 
arrays, but would rather use some kind of linked list.
If somebody knows a good and short structure, that uses
minimal memory, I would appreciate it if they would mail
me at sofmac at porthos.rutgers.edu

   thanks in advance
	     -- Sofus