Gekizoku said:
In response to the link Candor posted, I wonder if the Quincy dimension could be beneath hueco mundo, which remains largely unexplored.If you're talking about what's beneath Hueco Mundo then that was explained, underneath it lies the Menos forest as mentioned in the 3-episode Ashido filler (Kubo wanted to put it in the manga but the editor told him not to due to it being not that important or something like that). If you're talking about another dimension then dunno about that, the Ice Palace should be under somewhere, so either Hueco Mundo or the Living World or Soul Society, but there are lots of questions about that palace, so who knows.