We may not have gotten to the center of the Earth yet, but we have a pretty good idea what we’d find there. The solid ball of minerals that scientists suspect is down there is way less interesting than the way-out sci-fi ideas pictured in these 1969 Japanese magazine drawings.

The magazine tells the story of a group of adventurers who journey into the hostile and uncharted land at the center of our planet. The diagrams above show what can be found far, far beneath the crust: a whole other Earth.

According to the unbelievably awesome story told here, the center of the planet holds a sort of lost world/alternate reality. There are dinosaurs, giant mushrooms and terrifying huge animals.

It looks like the deep-subterranean people are an advanced civilization in some ways but entirely primitive in others. On the one hand, they’ve got a pretty complex tunnel transit system.

On the other hand, there seems to be a primitive death match going on between some kind of caveman and a giant tiger while pterodactyl-headed creatures and chimpanzees look on in amusement.