My theory

It's not a simulation/government experiment, but rather entire separate pocket Universe, or space anomaly if you wish. I think if we get enough seasons they will delve more into town's history and maybe we will find out that it was created/came to be during Mayan/Indian cultures.

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A lot of the imagery from the caves pushed me to this thought, as well as space where Martin was. It looked like a ritual site and there were people chained to the wall, perhaps a sacrifice to some beast/god or some sort of demon.