|The following is based on the canceled Fallout movie and has not been confirmed by canon sources.|
The L.A. basin was set to appear in the canceled Fallout movie.
A massive tangle of mutated flora and fauna spreading from the foot of the hills all the way to the ocean, poking up through the canopy were the remains of the scattered L.A. skyline. The Master turned the basin into a jungle with stolen G.E.C.K.s. Los Angeles became a cattle field for humans, an inviting oasis amidst the wasteland. The Forced Evolutionary Virus converted humans to superhuman mutants in hours.