It goes back to ancient times of the giants. A giant shaman was creating teleport foci for various locations of importance around the giant empire to teleport to, and at the time there was a floating bar high above the present day marketplace (keeps it out of reach of various lesser races). The shaman, being a frequent to the bar, created this teleport point. Unfortunately, to this day, Twelve mages are baffled as to how they remove this focus completely from use, so from time to time, it will pull random unsuspecting mages into the area. Removing giantish spellcraft, it appears, is very difficult when the original caster in question was drunk. Giantcraft is confusng enough without that.

-Jayron