Thread: underground civilization/city? ?

is it possible for there to be a HIDDEN underground city full of who knows what right beneath our feet?? i know there's the inner and outer core of the earth and the mantle but is it possible for there to be something in between the mantle and the crust of the earth? or have scientist already figured out and proved that there is absolutely NOTHING underneath us throughout the whole planet? meaning no life underneath us whatsoever

No civilizations. They would need agriculture which would need sun light. And there are some species of fungi that live deep underground. And other burrowing animals.