In Pixar's Monsters films (Monsters Inc. & Monsters U), the Monsters living on an Earth-like planet that is clearly not Earth. Via their special doors, they're able to come to Earth. It's unclear to me though how their planet and Earth are related. Is the Monsters' planet in a parallel dimension? Is it elsewhere in the same universe? Is the Monsters' planet Earth in the far future ala Planet of the Apes?

How are Earth and the Monsters' planet related/connected?

  • 1
    Monster Earth = Regular earth at the exact same place in space-time, just an alternate universe. Unless, of course, you believe in the Pixar Theory. In that case, it is a-la-Planet of the Apes with time travel.
    – Kaz Wolfe
    Oct 7, 2014 at 9:15

3 Answers 3


I'm not at home to confirm this from the dvd/blu-ray, but according to The Pixar Wiki

According to a DVD bonus feature, Monstropolis was founded after all of the monsters, who once co-existed with humans, were all chased off the mainland, and eventually moved to an island in an unknown part of the world (which Monstropolis is implied to be located) where they have lived ever since, and that the only way for them to enter human-inhabited areas was via closet doors.

So, "Monster's Planet" is supposed to be Earth.

  • I don't buy it. They're clearly depicted operating in the 20th century or even the 21st. We can tell from the elements and furniture in the children's room. A city of 25,000 or more macroscopic monsters using electric lights at night? No way to hide that on Earth, not in this time period.
    – John O
    Jul 11, 2013 at 22:41
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    Since monsters use advanced "door" technology, they might have also invented a stealth technology that hides their island. Jul 12, 2013 at 2:25
  • @sm4: But the humans put them on the island in the first place, so... Ugh, the whole Mount Ebott explanation really doesn't make sense here.
    – Kevin
    Sep 1, 2019 at 5:41

The film's director, Pete Docter stated in the accompanying Artbook that Monstropolis is a parallel universe to our own and that monsters have been around for a considerable amount of time. No mention is made to their having lived in our world prior to the building of the monster cities but given that door technology appears to be relatively recent, presumably there were earlier (less reliable? less sophisticated?) ways of traveling between the worlds:

"In 1997 we began to design the parallel universe we called Monstropolis. While our development team was working at Pixar, we also commissioned some of our favorite children's book illustrators to do inspirational designs. After I gave them a brief summary of the story, each illustrator was given freedom to design his or her unique vision of the monster world."


Monsters may creep out of our closets, but they don't live there. What do their homes, their cars, and their cities look like? Early on. the sky was the limit. But as we thought about it more, a few facts came to influence our designs:

Monsters have been around for as long as there have been frightened humans. The city's design should reflect this long history.

Quotes from The Art of Monster's Inc: Monstropolis


According to the Pixar Theory (all Pixar movies share a common universe), which has received an official nod, the Monsters movies are set on a future Earth. Sometime after the events in Wall-E.

So what happens? Humanity, machines and animals grow in harmony to the point where a new super species is born. Monsters. The monsters civilization is actually Earth in the incredibly distant future.

Where did they come from? It’s possible that the monsters are simply the personified animals mutated after the diseased earth was radiated for 800 years.

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