A world that contains access to many others, most of which are themselves unaware of the existence of portals/other worlds. Where the Portal Crossroad World is populated and has widespread portal travel, expect the culture to be a strange mishmash of elements from other worlds. Compare Portal Network, more often found in sci-fi where many worlds are equally interlinked by a portal transport system; contrast Void Between The Worlds, the space through which the portals pass. Also compare Inn Between The Worlds, the single-room/building version which is itself outside reality. This is a common form of the video game mechanic, Hub Level.
- In The Incredible Hulk issue 300, Dr Strange send a mindless rampaging Hulk to the "crossroads" from which he can enter any other world he wants, the plan being that the Hulk will find a world to his liking. If he enters a world and doesn't like it, Strange has placed a subconsious trigger in the Hulk's head to send him back to the crossroads again.
- Treasure Planet itself is a planet-sized portal generator created long ago that was discovered by pirate Captain Nathaniel Flint. Flint used the portals to surprise merchant ships and plunder them ruthlessly, then store the captured booty on the centroid of the portal mechanism. This was how Treasure Planet got its name.
- Contact has Hyperspace Lanes from many worlds all leading to the one place where the aliens bring new sentient species to introduce themselves.
- In KJ Taylor's first book, The Land of Bad Fantasy, the protagonist comes from one of these, called Y'hyerd B'zeck. There, interdimensional travel is so common that there are various Advice for Dummies books about it, aspects are taught in school, and there is no semblance of whatever their original culture was.
- The world of ''The Subtle Knife, has many portals thanks to the titular object.
- From Stephen Donaldson's Mordant's Need series, Mordant is this through the use of Imaging and the mirrors.
- Quentaris with its rift caves (acts mostly as a one-city-world) is a variation. While many worlds trade through the rifts, many also do not know of their existence. Quentaris also has a greater concentration of rifts than any of the other worlds, which have few or none.
- The Magicians Nephew has a universe/dimension referred to only as "The Wood Between the Worlds". It's a forest that stretches as far as the eye can see, dotted with pools of ankle-deep water. With the proper magic (such as the rings created by Digory's uncle) any of these pools can become a portal to another universe, like our Earth or the land of Narnia.
- The Arena in Grand Central Arena, where every spaceship with a drive for Faster Than Light Travel ends up.
- The Nightside from Simon R Green's novel series is a hidden urban center full of Timeslips to distant eras or alternate histories, passageways to alien realities and planes of existence, and Bigger On The Inside pocket dimensions. Characters such as the Doormouse or the proprietors of the Mammon Emporium have actually commercialized this trope, using portals for architecture, transportation, and importation of exotic goods.
- Crossroad of Nick O'Donohoe's Crossroads trilogy (The Magic and the Healing, Under the Healing Sign, and The Healing of Crossroads). Some inhabitants there can go to and from there at will, but most end up there by mistake. It's very much a refuge of mythological species.
- The city of Sigil in Planescape is also known as the City of Doors, because there are gateways to all known and unknown planes there.
- In the Forgotten Realms, one drow city has a whole bunch of portals to various places on the surface, and so is commonly used by raiding parties from various other cities.
- Mortal Kombat Deception introduced the Nexus, a void-based Hub World of sorts that opens portals to other realms with the use of the Kamidogu.
- Chrono Trigger has the End of Time, a dimension that exists after time is eaten, containing portals to the different eras and can be used to access an early-game Peninsula Of Power Leveling.
- Super Mario 64: The paintings in Peach's castle act as portals to each of the game's 11 stages, which Mario has to enter to retrieve the Power Stars.
- Near the end of Bioshock Infinite you will enter one of these and travel around to different Alternate Universes.
- The planet Freleng lies at the center of the galaxy in the Loonatics Unleashed universe, where it functions as a portal junction. Control of planet Freleng is critical to a trio of villains bent on galactic conquest.
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