Hollow Earth

The Hollow Earth, known to the Iwi as the Long Ago Below, is a location that was discovered in the 2019 film Godzilla: King of the Monsters. It is an ancient subterranean ecosystem deep within the Earth, close to the planet's core. Its gravity is unique and inverts at a halfway point, allowing Titans to walk freely on both floor and ceiling of the Hollow Earth without fear of falling from one to the other. It's surrounded by a gravitational-electrostatic "membrane" anomaly inside the Earth's mantle. The ecosystem continually radiates radioactive energy, allowing the creatures that inhabit it to evolve to titanic sizes. A fortress belonging to Kong's species also exists there, with a throne once held by his ancestors.