Project Rebirth was a secret United States project to produce a Super-Soldier. Rebirth was created prior to America's entry to World War II. Steven Rogers became the project's candidate and was injected with the Super-Soldier serum that made him to become Captain America.
After Rogers was lost in the North Atlantic, Rebirth was shut down; or at least it was supposed to be. Rebirth was later reinstated in response to the looming threat of the Soviet Union at that time and the existence of extraterrestrial threat. Two Rebirth devices that enhanced Captain America (and almost killed him even with the Super-Soldier serum within his body) were created; the first was destroyed and the other was used as a backup.
Magneto and the Acolytes broke into the facility housing Rebirth, and stole the Rebirth device and kidnapping Dr. Bruce Banner, the lead scientist of the project. Magneto wanted the device, as its effects prolongs the life of mutants and wanted to use it on himself as he is dying. Magneto succeeded in using the device, but it was then shortly destroyed by explosive charges set up by the Avengers, X-Men, and Superman.