Earth

Earth (or The Other Side) is an alternate universe that lies on the other side of The Gate. This realm appears exclusively in the 2003 anime.

Overview
In Episode 50, Edward Elric first appeared on Earth after Dante uses Rose's child to summon The Gate and forced him on the other side. Upon awakening, Ed found himself in London, where he encounters Hohenheim of Light and finds himself in the body of his parallel counterpart. Hohenheim reveals that the souls of those who die in this world are transformed into energy for Amestrians to use Alchemy. Meanwhile, both Ed and Hohenheim watch as the city is in chaos, with Zepplin's bombing the area, that cause debris to land on Ed, his counterpart dies, causing Ed to return through The Gate back to Amestris.

In Episode 51, Edward is once again transported back to Earth as the price for resurrecting Alphonse Elric. Ed and Hohenheim were living together but later went their separate ways on a journey to find a way to return to Amestris: Ed aspires to learn about rocket science, while Hohenheim plans to seek out Winston Churchill), with Ed promising to reunite with his brother.

Earth has a more prominent role in Conqueror of Shamballa, where the main antagonist Dietlinde Eckhart and the Thule Society aspire to reach "Shamballa" after gaining the knowledge from Hohenheim. At the end of the movie, Edward (and Alphonse, who stowed away inside a suit of armor) decide to leave Amestris behind to destroy The Portal from the alternate side of The Gate and settle in this world.

Technology
As stated by Hohenheim of Light, this realm relies more on physics and machinery than alchemy, because of this, any special abilities an Amestrian has (via Ed and Hohenheim's alchemy, or Envy's shape-shifting) are nullified. However, it appears that an Amestrian can use some form of alchemy (usually in an attempt to open The Portal) with their blood - although, this could also be attributed from the unknowing assistance from someone else in Amestris (like Alphonse).

Aside from the lack of alchemy, the realm of Earth at the time possessed Bi-planes, Airships, Zepplins, Pistols, Suits of Armor, the Spears of Longinus, Vehicles, along with other equipment to function.

Inhabitants
Edward Heiderich (deceased)

Alfons Heiderich

Officer Hughes

Gracia the Florist

Noah

Fritz Lang

Erik Jan Hanussen

Adolf Hitler

Dietlinde Eckhart

Karl Haushofer

Rudolf Hess

Trivia

 * Many fans have used the term "Our World" to describe Earth.
 * It's stated that anyone that crosses over this side (with their mind, body, and soul intact), will find it next to impossible to return as alchemy does not work on Earth.