Cradles are cryostorage and child-rearing facilities built to service the ELEUTHIA function of Project Zero Dawn. These numbered underground bunkers were constructed around the world to eventually repopulate the Earth with humans once the biosphere was returned to a habitable state.
The Cradles were designed to re-introduce humanity to the world once the biosphere had been restored to habitable levels. To do so, they contained zygotes stored in cryogenic suspension, as well as artificial wombs for gestation, child-rearing facilities, and automated multi-servitors to serve as parental figures for the children.
A central part of the Cradle facilities was the implementation of APOLLO, which would educate the new humans about the Old World and how not to repeat their predecessors' mistakes. However, due to Ted Faro's sabotage, this would never come to fruition.
Dr. Sobeck's hologram introduction to GAIA included a map of planned Cradle locations: these locations included present-day France, Russia, India, Afghanistan, and Greenland. However, given the speed of the Faro Plague's advance, it is unclear how many of these Cradles were completed in time. Based on the numbering system, it can be presumed that at least nine Cradles were completed before the Faro Plague.
- ELEUTHIA-1 was constructed somewhere near the Xinjiang province in northwest China, narrowly avoiding the Faro Plague. 
- ELEUTHIA-2 was constructed inside Mount Namuli in Mozambique. Based on Sobeck's hologram, at least two more were planned for construction in Africa.
- ELEUTHIA-9, the only Cradle seen within the game, was constructed in Colorado, USA.
The locations of ELEUTHIA-3 through ELEUTHIA-8 are unknown.