Hollow Earth

Hollow Earth is a theory that says there is an entire world underneath the ground that we live on. It suggests that there are secret cities, rivers, plants, and even people living below the surface of the Earth. The idea of Hollow Earth is a bit like a fairy tale—it might be real, but it isn't proven to be true. Some people believe that there might be a secret underground world that has been kept hidden from us, but there is no scientific evidence to support this idea.