Earth-2

Earth Two is a universe parallel to Earth One. The name was coined by Martin Stein. To its own citizens, it is called Earth One.

History
A conflict called the War of the Americas happened sometime during the 20th Century. James Zolomon fought in it.

Sometime on a voyage, Oliver Queen and Robert Queen were involved in a violent shipwreck which took the life of the former. Robert eventually made his way back home and became the vigilante known as "The Hood" and later "The Arrow".

In 2013, the particle accelerator from S.T.A.R Labs exploded, giving many civilians including Hunter Zolomon special powers. This prompted S.T.A.R. Labs of its studies in meta-humans. Various meta-humans such as Atom-Smasher, Sand Demon and Doctor Light became corrupt with their powers and became criminals. with Reverb becoming a prominent crime boss. Sometime after Hunter Zolomon, later known as Jay Garrick, became the Flash, a future Hunter showed up, known as Zoom, the two becoming enemies, with Reverb acting as Zoom's main agent.

On May 19, 2015, a singularity breached the world, originating from Earth One. As a result, Jay Garrick was sucked through. Zoom discovered how to cross the dimensions, and brought meta-humans between the worlds to assist him in his mission to kill the Flash.

For the next few months, the Flash team were forced to face various dimensionally-displaced metahumans as well as their own "local" threats, with Zoom even mounting a direct attack that saw him break Barry's back before he had to retreat when he was injected with a speed-supressing serum. When the Earth-Two Harrison Wells travelled to Earth-One to hunt the metahumans, Zoom attempted to blackmail Harry to help him take Barry's speed by threatening Harry's daughter Jesse, but when Barry learned the truth, he decided to help Harry rescue Jesse. After sealing the other breaches, Barry, Harry and Cisco travelled to Earth-Two to try and rescue Jesse and confront Zoom, which also led to a confrontation with Killer Frost, Reverb and Deathstorm that saw Reverb and Deathstorm being killed by Zoom after they killed Joe West. Barry and his allies were eventually able to escape Zoom's prison and rescue Jesse with the aid of Killer Frost, but Jay Garrick was apparently killed by Zoom before they could seal the final breach.

Locations

 * Big Belly Burger
 * Central City
 * Central City Orphanage
 * S.T.A.R. Labs
 * Atlantis
 * Starling City
 * Gorilla refuge
 * Zoom's lair
 * Jitterbugs

Known individuals

 * Barry Allen
 * Barry Allen's father
 * Barry Allen's mother
 * Bruce
 * Diana
 * Eddie
 * Adam Fells/Geomancer (deceased)
 * Hal
 * Henry Hewitt
 * Knowles
 * Shay Lamden/King Shark (currently on Earth One)
 * Floyd Lawton
 * Linda Park/Dr. Light (currently on Earth One)
 * Oliver Queen (deceased)
 * Robert Queen/The Arrow
 * Jesse Quick (currently on Earth One)
 * Cisco Ramon/Reverb (deceased)
 * Ronnie Raymond/Deathstorm (deceased)
 * Al Rothstein/Atom-Smasher (deceased; killed on Earth One)
 * Singh
 * Eddie Slick/Sand Demon (deceased; killed on Earth One)
 * Patty Spivot
 * Martin Stein/Deathstorm (deceased)
 * Snart
 * Caitlin Snow/Killer Frost (deceased)
 * Dr. Harrison Wells (currently on Earth One)
 * Iris West
 * Iris West's grandfather
 * Joe West (deceased)
 * Ashley Zolomon (deceased)
 * Hunter Zolomon/The Flash/Zoom
 * James Zolomon
 * Zoom's masked prisoner
 * Caitlin Snow (captive)

Trivia

 * Although comparable events on Earth One and Earth Two seem to happen roughly at the same time, there might be a global shift of the timelines with respect to each, as evidenced by the fact that Harrison Wells founded S.T.A.R. Labs in 1991 on Earth Two while his counterpart from Earth One (as well as Eobard Thawne in the altered timeline) founded S.T.A.R. Labs at the earliest in the year 2000. This apparent mismatch of events on the two Earths might be explained by the nature of the singularity and the breaches, connecting Earth One and Earth Two, possibly representing a gateway through both space and time. However, if the timeline of Earth Two was really somewhat ahead of schedule with reference to Earth One, it could explain why Harrison Wells of Earth Two could start the particle accelerator already in 2013 (possibly without the help of Tess Morgan), while his counterpart from Earth One accomplished that goal as late as 2020.
 * This version Earth Two seems to be an amalgam of Earths Two and Three from DC mythology. It features villainous versions of heroes or civilians from Earth One (Linda and Al Rothstein), similar to Earth Three, but features the same heroes from Earth One, but with different civilian identities than those of Earth One (Jay instead of Barry; Robert instead of Oliver) such as on Earth Two.
 * Stylistically Earth Two's Central City has a late 40s-50s aesthetic, presumably as a reference to the real world 1940s and 1950s (also known as the Golden Age of Comics). During this time The Flash character was first created, with Jay Garrick as his first civilian identity.
 * Television and computer screens on Earth Two are vertically rectangular rather than horizontally.
 * Blood types are different on Earth Two. Harry remarks that Jesse has "PZ Negative" blood. His Blood type is unknown but is apparently a match.
 * Although most differences between the residents of Earth One and Earth Two are seemingly based around nothing more than them making different choices, a more subtle difference has been revealed, as Caitlin Snow of Earth One has explicitly confirmed that she does not have the meta-human gene while Killer Frost became a meta-human in the particle accelerator explosion of Earth Two; other differences could be based on circumstances.
 * Harry claims that serial killers are "an anomaly" on Earth Two. Hunter Zoloman's conviction was met with massive media coverage.