Phoenix is a town that Noah Shackleton and the Co-operative designed to keep genetic candidates whose systems could resist Tabitha. It was built for the purpose of keeping those in Phoenix, in Phoenix. Phoenix is designed to host a certain number of families--families with a special gene that is immune to Tabitha. For these reasons, the phones don't work, there is no Internet, and they don't even allow cars (This could be because the Co-operative didn't allow pollutants or so citizens could use them to escape by way of ramming the stone walls which encircle Phoenix). It is presumed that Phoenix is in the middle of the Australian Outback but is never mentioned. It is surrounded by an impenetrable massive stone wall that let noone in or out, revealed near the end of Arrival. It also seen that at the end of Fallout that the big metal cords that were connected to the wall was part of an extremely secure electric grid so that, when the cords attached themselves to the antenna of the the Shackleton building, it creates an electric force field around Phoenix, making it nearly impossible for anybody to escape or rescue.