The Infinity Stones are the Marvel Cinematic Universe’s big McGuffin. They’ve been present ever since the Tesseract was introduced into the series, but they were officially introduced in Guardians of the Galaxy when The Collector explained that before the universe first began, there were six singularities. These six singularities were then condensed into concentrated ingots. Whoever controls all six stones and wields them using the Infinity Gauntlet has the power to reshape reality.

So where are the stones and what exactly do they do? With Avengers: Infinity War now ehre, we’re running down what we know about the Infinity Stones in the MCU thus far. [Spoilers for all Marvel movies through Avengers: Infinity War]

Space Stone

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Image via Marvel Studios

Originally introduced as The Tesseract in Captain America: The First Avenger (although technically it first appears in the post-credits scene of Thor), the Space Stone has the power to all interdimensional space travel. While Red Skull used the power of the Tesseract to create super-powered weapons for Hydra, Loki used the Tesseract to open a portal, which allowed the Chitauri to attack New York City in The Avengers. At the end of the movie, the Avengers retrieve the Tesseract, give it to Thor, and he puts it in Odin’s treasure room for safekeeping.

Thor: Ragnarok added a new wrinkle when Loki heads down to the treasure room to put Surtur's helmet into the eternal flame and spots the Tesseract. We never see Loki take the Tesseract, but Loki gonna Loki and he pocketed it. The Tesseract is on the Asgardian ship when Thanos and the Black Order arrive.

Reality Stone

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Dubbed “Aether” in Thor: The Dark World, the Reality Stone, according to Odin, “changes matter into dark matter” and the villain, Malekith, wants to use it to return the universe to darkness where he and his dark elves reigned. When the Aether, which usually appears in liquid form, is contained in a stone at the end of the film, Sif and Volstagg bring into The Collector for safekeeping. They explain that they’re giving him the stone because it would be unwise to keep more than one stone in Odin’s treasure room. After they leave, the Collector ominously says, “One down, five to go.”

Power Stone

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Hidden in an orb that Guardians of the Galaxy's Peter Quill discovers on the planet Morag, the Power Stone gives the person who wields it the power to destroy an entire planet as its power is proportional to the organic matter it touches. The Power Stone cannot be held for more than a few moments unless that power shared is between people, and even then it’s only for a limited time. The stone requires a weapon of some kind like Ronan’s hammer or the Infinity Gauntlet in order to be used without destroying the bearer. The Guardians of the Galaxy are able to recover the stone from Ronan, encase it in a new orb, and give that orb to the Nova Corps on Xandar for safe keeping.

But it looks like they didn't keep it too safe. We're told in Infinity War that there was a raid on Xandar that decimated the planet and Thanos absconded with the Power Stone.

Mind Stone

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This stone originally appeared inside the blue orb from the scepter that was given to Loki by Thanos. Whenever Loki touched the scepter to someone, it allowed Loki to control that person’s mind and do his bidding with the only way to break the spell being a serious concussion. When the scepter is recovered at the beginning of Avengers: Age of Ultron, Tony Stark and Bruce Banner use its power to give life to Ultron, which (spoiler alert) backfires since Ultron is deeply evil and twisted. He then breaks the stone free from the scepter and implants in the android Vision. The stone, the vibrainium used to make the android, a special chamber and a lot of electricity from Thor’s hammer, gives life to Vision, who still has the stone implanted in his forehead. It currently gives Vision the power of flight, super strength, the ability to phase through solid material, and the ability to shoot energy beams from the stone.

Time Stone

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The Time Stone rests inside the Eye of Agamotto pendant revealed in Doctor Strange. The Time Stone allows the bearer to manipulate time, allowing them to either rewind or fast-forward through events or create a time loop. Strange does both during the film, first using the stone to rewind events when they arrive in Hong Kong and then trapping himself and Dormammu inside of a time loop so that Dormammu can’t destroy the Earth. At the end of the movie, Strange returns the Eye of Agamotto to Kamar-Taj, but as we see in Infinity War, he likes to keep the Eye on his person.

Soul Stone

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If the MCU goes by the original stones (called Infinity Gems) in the comics (and so far they have), then the last remaining stone is the Soul Stone. In the comics, it allows the bearer to manipulate the souls of the living, opens up a gateway to an idyllic pocket universe, can steal the powers and abilities of others, and at its full potential gives the user power over all life in the universe.

Oddly, we never learn what the Soul Stone really does when it's dropped into Avengers: Infinity War. We learn that the Stone is hidden on the planet Vormir, and only Gamora (Zoe Saldana) knows the location. She agrees to take Thanos (Josh Brolin) so that he'll stop torturing Nebula (Karen Gillan), and when they arrive, they run into Red Skull, who agrees to show them how to obtain the Stone. The Stone can only be obtained by someone sacrificing what they love most in the world--a soul for a soul. Setting aside that this is a paradox (the thing you would love the most would be the Stone itself so you'd really be killing the thing you love the second-most), Thanos sacrifices Gamora and obtains the Soul Stone.