Board Thread:Questions and Answers/@comment-61022-20160330220251/@comment-61022-20160401201225

The differences between Forest Hilly/Holy Wood and Yinsen City/Mondo City is that these were domains separated by a wall, one breached the other or there was cross domain travel, or domains were annexed into others. Same could be said about Utopolis, Europix, etc in the Squadron Sinister story.

The main difference is that each of those domains were chunks from other realities that had defined borders and there wasn't a literally merger, only a change in the physical border and boundaries of those domains. Physically they are still separate places and belong to other distinct and separate realities. Only the political borders were broken and political power merged or usurped.

Whereas the Kingdom of Manhattan was literally a merger of two domains due to both Tony Starks fiddling around with the portal device. Since the merger of two different domains resulted in the creation of a merged reality of Earth-61610, then obviously the Starks portal device created a physical merger as opposed to a superficial one. One that was so total that, when reality was restored, instead of two distinct realities, it was restored as one merged reality.