[SPOILERS] How big would the hole to the Dark One have had to be...

[agreddon]

For him to actually break through?  You would think pretty big for a cosmic embodiment of evil/chaos/destruction/whathaveyou, but when Rand pulls him out during AMOL, he's described as small as a bird.  So how big would that hole have had to be?  Or was there something else binding him that had to be destroyed first?