The MCU has introduced several different ways to travel through the multiverse and its many dimensions. Throughout Phase 4, the scope of the MCU's multiverse has grown at an incredible rate, presenting various alternate realities filled with different versions of familiar faces and even brand-new characters that don't exist in the main MCU universe. But while the multiverse has taken a central spot in the franchise, there are still more questions than answers regarding its nature.
Like superpowers, deities, and sorcery, the multiverse can be approached through both scientific and magical means. Scientists like Hank Pym and magic users such as Doctor Strange and Scarlet Witch have made important discoveries about the multiverse, but not even they have a strong grasp of its inner workings. It seems that the multiverse is quickly becoming a big threat, and every time a character begins to understand it, another multiversal event arrives to shake things up.
The MCU has introduced universes like the Avengers' Earth-616, the Illuminati's Earth-838, and the Raimi universe. It also has featured dimensions such as the Soul World, the Ancestral Plane, and Ta-Lo. While these dimensions aren't exactly parallel universes, they're still extraneous realities that can't be accessed through regular means of space travel. Concepts like incursions and variants are yet to be fully explained, but if there's something certain, it's that there's more than one way to travel to other planes of reality. These are the ones introduced in the MCU so far.
Time Travel and The Quantum Realm - Avengers: Endgame
A dimension in and of itself, the Quantum Realm is so small that it is nearly impossible to even detect. Avengers: Endgame revealed that the Quantum Realm also serves as the key to time travel, which not only allows the Avengers to retrieve weapons from the past but also makes it possible to branch out the MCU's timeline. Fortunately for the multiverse's stability, the Avengers avoided altering past events, and the TVA ensured that the new timelines couldn't evolve into unique universes. However, Loki's escape with the Tesseract proves how dangerous time travel could become. If a minimal change means an entirely different person can come into existence, then time travel could be the perfect tool to create infinite universes, if it falls into the wrong hands.
The TVA and The Citadel at the End of Time - Loki
The TVA managed to stop the Sacred Timeline from collapsing thanks to He Who Remains, who protected it — seemingly —out of sheer generosity. The organization could travel to any point in the timeline with the help of an arsenal of high-tech tools such as TempPads and Time Doors, which seem to merge time travel with teleportation and magic. Things may actually be more complicated than the TVA made them seem, however, as different variants were allowed to exist only until they made a certain decision. This means that other parallel universes have always existed and that the TVA allowed them to remain free as long as they didn't threaten their overall plans. Somewhere out there, the home universes of variants like Sylvie Laufeydottir, variant Alligator Loki, and Throg could continue to exist as unique realities.
The TVA itself exists outside of space and time, which means that arriving at their headquarters counts as multiversal travel. But the TVA also has access to other planes of existence: the Void, where all pruned variants are sent to live forever, and the Citadel at the End of Time, where He Who Remains protected the Sacred Timeline for eons. Access to the TVA, the Void, and the Citadel at the End of Time is possible thanks to He Who Remains' 31st-century technology, which is advanced beyond comprehension. Only Kang the Conqueror's arrival could provide some insight into how He Who Remains really took control of the multiverse. Given his connection to Reed Richards and Doctor Doom in the comics, it's possible that it may have also had to do with a fusion of science and sorcery.
The Nexus of All Realities - What If...?
Uatu and the Watchers inhabit the Nexus of All Realities, a dimension outside of the MCU multiverse where the Watchers oversee every existing universe. This place is supposed to be unreachable, as it isn't a regular universe but an outer dimension that links all universes together. However, an Ultron variant that harnessed the power of the Infinity Stones managed to see through reality itself and interact with Uatu.
Only beings of supreme power can sense the Nexus of All Realities, let alone travel to it. The Watchers are able to travel freely between the Nexus and each universe, but given that they took an oath to never intervene, they rarely leave their home. While the Nexus of all Realities is the dimension that binds all universes together, it is not the only place outside of space and time. Other similar locations include He Who Remains' Citadel at the End of Time and the Gap Junction, the latter of which houses the Book of Vishanti and could be accessed by Defender Strange.
America Chavez's Powers - Doctor Strange in the Multiverse of Madness
The fastest way to travel the MCU multiverse is through America Chavez's innate portal-summoning abilities. Doctor Strange in the Multiverse of Madness establishes that America first manifested this power when she was a kid, and that it only came to her at times she was scared. It took America Chavez time to harness her multiverse powers, but by the time she fought a one-on-one battle with Scarlet Witch, America was finally able to summon intra- and inter-dimensional portals. Doctor Strange in the Multiverse of Madness also revealed that America Chavez's powers can be stolen, as the Darkhold allowed Scarlet Witch to peek into other realities and Dreamwalk with her variants' bodies, but she needed America's multiversal portals to actually travel to other realities.
Magic Spells - Doctor Strange and Spider-Man: No Way Home
Magic may be the most important part of multiversal travel. In 2016's Doctor Strange, The Ancient One provided the first mention of the multiverse when she told Stephen Strange that his reality "is one of many" and that sorcerers "harness energy... drawn from other dimensions of the multiverse." And in the same movie, Kaecilius was able to access Dormammu's Dark Dimension through magic alone. The Ancient One and Doctor Strange mastered their ability to summon the Mirror Dimension, and in Avengers: Infinity War, Doctor Strange saw 14,000,605 futures, each of which could have unfolded into unique universes.
In Spider-Man: No Way Home, Doctor Strange's memory-wiping spell caused multiversal invaders to land in the MCU's main universe, but he used other magical tools such as the Macchina di Kadavus to send the variants back to their home universes and close the multiversal rift. Soon after, Doctor Strange and Scarlet Witch used the power of the Darkhold to possess the bodies of their multiversal variants, effectively sending their consciousness across the multiverse. This method has negative side effects, however, as Scarlet Witch grew increasingly irrational and Doctor Strange developed a third eye that may or may not turn him evil.
The Convergence - Thor: The Dark World
Every 5,000 years, the Nine Realms align in an event that affects the whole universe. Asgard, Jotunheim, and Nidavellir may not be universes like 616 and 838, but they do exist in their own realm and can be accessed through magic means like portals and the Bifrost. While the Convergence doesn't involve other the entire multiverse, it may hide some multiversal secrets. Dr. Erik Selvig's research apparently studied the Convergence, the Nexus of All Realities, the Multiverse, and even the mysterious reason why the MCU's main universe is called Earth-616. Whatever causes the Nine Realms to converge, it surely has something to do with multiversal travel.
The Heart-Shaped Herb - Black Panther
Like the Quantum Realm and the Mirror Dimension, the Ancestral Plane doesn't seem to be a regular universe. Instead, it is a place where the rules of time and space are inherently different. The Ancestral Plane is where the spirit of all Black Panthers goes to rest in peace, and it allows them to communicate with their successors. Wakanda forged a spiritual connection with this plane of existence through the Heart-Shaped Herb, which is part of the ritual to become the Black Panther. Although it's a part of Wakandan culture, the Ancestral Plane is also adjacent to the Astral Plane, which sorcerers like the Ancient One and Doctor Strange send their souls when they separate them from their bodies. In Avengers: Infinity War, Thanos knocked Doctor Strange out of his body using the Soul Stone and the Power Stone, which suggests that the Soul Stone granted him access to the Astral Plane without having to be adept in magic.
The Infinity Stones - Avengers: Infinity War
Using all the Infinity Stones simultaneously sends the user to the Soul World, another dimension that exists outside of reality. The Soul World is the dimension that looks the least like a regular universe. It is an infinitely empty space that only materializes people that are important to the visitor. The Soul World is shrouded in mystery, as it is intimately connected to the very soul of living beings. While it has been theorized that MCU characters go to the Soul World when they die, this is unlikely, considering that its infinite nothingness doesn't contain anything beyond what the Infinity Stones produce.
The Path to Ta-Lo - Shang-Chi and The Legend of the Ten Rings
On the other side of the spectrum, the mythical land of Ta-Lo is the dimension that looks the most like a regular universe. Ta-Lo doesn't exist anywhere on Earth. Instead, it's a pocket dimension of its own, which houses fantastical creatures like the Dijiand and powerful entities like the Great Protector. The only known way to reach Ta-Lo is through a hidden bamboo maze, and only at the start of the yearly Qingming Festival. Given that Ta-Lo looks like an Earthly town, it's unknown what would happen if somebody tried to fly to outer space there. If there's an entire universe outside of Ta-Lo, then it could be classified as its own reality within the MCU multiverse.
Death - Moon Knight
Not all dimensions can be accessed by moving through space. Some are reached by dying. When Marc Spector is shot and killed by Arthur Harrow, he arrives at Moon Knight's version of the afterlife, in the form of a psychiatric hospital. This is the Duat, the astral dimension of the Egyptian underworld. The goddess Taweret explains to Marc and Steven that the only way to escape the Duat is by weighing their heart against a feather. If the heart is heavier, the soul is frozen in the desert for eternity; if not, it goes to the paradisiac Aaru. In very special cases, Taweret might help the soul come back to life.
Kamala Khan's Bracelet - Ms. Marvel
Yet another dimension was unexpectedly introduced in Ms. Marvel, where Kamala Khan's bracelet awakened her connection to the Clan Destines. These individuals, often confused with Djinn, were exiled from the Noor Dimension in Ms. Marvel — the place from where Kamala draws her power. The exact details of how to access it have not been fully explained, but if the ClanDestines actually hail from there, it's possible that Kamala will eventually be able to visit it. Like the Soul World or Ta-Lo, the Noor Dimension is one of the many places in the MCU multiverse that can be reached with the right tools.
