to stop Krona from splitting the Universe and stop the Anti-Monitor from altering the moment of creation and make the Antimatter Universe the only one. They succeed in saving all existence but in the process, the Multiverse, its countless duplicate worlds and its history ceased to exist. The five universes that were saved were folded together into a single universe, placing all the heroes and villains into a single timeline. For example, Justice Society of Earth-Two instead became a team active in the 1940s that inspired the Justice League to form decades later. In the event of any duplicate characters, the original Earth-One version would take precedence. All the universes existed within the same space, but had a unique vibration that kept them separated. Only by "tuning" to the specific frequency of a universe could a person leap to another Earth, as Barry Allen discovered as he tried to perform a disappearing act by vibrating his molecules at super-speed (Flash #123). The "speedster" later developed a machine called the "Cosmic Treadmill", which, when it was used by people who controlled the Speed Force, it allowed the users to trespass the "vibrational barriers". Magic and cosmic incidents also made many people to travel to other universes. Every universe could have its own dimensions, such as the Fifth Dimension (where Mr. Mxyztplk (Earth-Two), Mr. Mxyzptlk and Bat-Mite (both Earth-One) came from), alternate timelines (Kamandi and the 30th century of Earth-One) and realms (Hell, Heaven, Gemworld, etc.). In addition to the unique Antimatter Universe, the dimension of the New Gods (the Fourth World) was also believed unique, although there is evidence that there could have been alternate versions of them (as those appearing in Earth-17 and Earth-Crossover). Even though the interaction between multiple Earths was common in the 20th century with relative safety and ease, most of the population of Earth was unaware of the Multiverse until the Crisis on Infinite Earths. DC Universe and Megaverse 15 billion years ago, a single universe with a single timestream was created. 4.4 billion years ago, Krona, the renegade Maltusian (a race of highly evolved beings) creates the Antimatter Universe and releases entropy in the universe by linking the beginning and the end of the timeline in his attempts to reveal the secrets of the creation of the universe. In this single universe, the timeline was destroyed in the early 1990s by Hal Jordan (possessed by