The legend of Agartha and the Hollow Earth
The first public scientific evidence occurred in 1947 when Rear Admiral Richard E. Byrd of the United States Navy flew directly to the North Pole and instead of going over the pole, actually entered the Inner Earth.
In his diary with other witnesses, he tells of entering the hollow interior of the Earth, and traveling 1700 miles over mountains, lakes, rivers, green vegetation and animal life. He tells of seeing monstrous animals resembling the mammoth of antiquity moving through the underbrush. He eventually found cities and a thriving civilization.
Admiral Byrd also states Inner Earth has an inner Sun. Admiral Byrd’s theory is that the poles of the Earth are convex, rather than concave. Ships and planes can actually fly or drive right in.
This is absolutely fascinating, and the sourced site is full of information.