1920s England is a world featured on Once Upon a Time.
Before First Curse
After Fifth Curse
In order to unite all the realms as one, Regina Mills recasts the Dark Curse with a slight variation. The curse spreads into 1920s England, ripping everyone and everything, destroying the realm. 1920s England then merges with other realms which forms the United Realms. ("Leaving Storybrooke")