Earth

Earth is a planet, and a completely unique one at that. It is only one of two planets in the OU to suffer from the same temporal dysfunction - whenever it is destroyed, a new version of the planet appears to take its place. The Chronicler explains this as being because, at the time of the multiverse's creation relative to Earth's time, the human race had created so much fiction that sixty billion unique versions of Earth took their place in the multiverse at the same time, occupying the same space. Destroy one, and it is replaced by the next from the assortment. Humanity collectively describes this day as "the day the world went mad". The other planet which shares this distinction is Tybion, though the reason why is unknown.

Because of this, Earth has been destroyed several times in large-scale conflicts or terrorist attacks, only to be replaced by more Earths one at a time, each with a unique history. Recently though it has been left mostly ignored by hostile forces, with attention instead being turned to the planets involved in the Uterio War.

United States of America

 * Miami, Florida - The home of Great Being Michael Weston. The Toa Idiotas fought him here, and ended up destroying a restaurant in the process. It is also the home of Dirk Strider and the site of a battle between the Black Pearl and an army of Underlings.
 * Wall Street, New York - Ross Mandell's turf. He also stole Doug Walker's $200k here by tricking him into thinking he was his blackmailer.
 * Chicago, Illinois - The location of Doug Walker's house, where many members of the comic reviewing community congregate, including Dr. Bedge.
 * Area 51, Nevada - A top-secret government facility used to store alien technology. Jesse Ventura visited it once, and broke Tommy Wiseau out of captivity.
 * Task City, Arkansas - A large city that serves as the setting of Mysteries Unlimited.
 * Mount Justice, Rhode Island - The location of the Justice League's headquarters.
 * Detroit, Michigan - The meeting place of several pirates/mercenaries that Fourteen recruited into a team to break into Supermax 429.
 * Boston, Massachusetts - The location of Charlestown, a neighbourhood where the ZFT set off a biological weapon that was investigated by the Fringe Division.
 * Cambridge, Massachusetts - The location of Harvard University, a building which contains Walter Bishop's lab.
 * Minnesota - The state that Ventura was once governor of.

United Kingdom

 * New London, England - The name of the city that was built upon the original London. Hungry-man and Skelly Bones! lived here for a while, and once scared some homeless people by eating chicken inhumanly quickly near them.
 * Shetland Islands - A group of islands that are home to Alexander Colmes and the Silverwood Estate.

France

 * Paris - Sasuken took Blue and Shikhazra on a date here.

Poland

 * Mad Scientist Convention venue - The Mad Scientist Convention was hosted here.

Tunisia

 * Sahara Desert - The exit point of "The Island", as visited by D-Klak, Nadle, Kakamu and Bob. This is also the location of one of Earth's Stargates.

Nauru

 * Aiwo - The location of a café that Time Guardians such as Quolas and Vexull used to meet in.

"The Island"

 * Quolas' fortress - The Time Guardian Quolas used to own a fortress on this time-travelling island from the TV series LOST. However, he has since been banished and the fortress reclaimed by the island's inhabitants.