From spherebeingalliance.com FAQ:
Is the earth hollow? And if yes what about the others planets in our solar system?
There is a “Honeycomb Earth” and not the “Hollow Earth” depicted in some of the images in books and on the Internet. The caverns that interconnect around the entire globe going many miles below the surface are so enormous that no one can even begin to imagine their size. There is also a series of ecosystems within them made up from very simple to complex life forms. For example there are a few types of algae like bacteria’s that “eat” the rock and release both a soil like debris as well as different colors of bioluminescence that provides a decent amount of luminosity for the other parts of its ecosystem. There are plants and animals as well as a list of documented higher level life forms that have both developed below ground, moved below ground in the distant past as well as some off world groups and break away groups that have taken advantage of the honeycomb network below ground for many hundreds of thousands of years. There is quite a number of extremely ancient and advanced technologies that was left behind by a group known to many as “The Ancient Builder Race”. It is said that the “Inner Earth” is littered with this technology. This technology is highly coveted by surface Human Groups, Break Away Groups and Off World Groups because of its uniquely advanced and multi-dimensional nature. Some who listened to my part 2 interview will remember I was brought to a “Living Energetic Crystal Cavern” far below ground when I was a pre-teen as a part of the “IE” training when I was in the MILAB Program. As far as the other “Rocky Planets” in our Sol System I assume they are similar. I know Mars has some similar areas because of some reports and images I was shown at one point. Anything further would be speculation. It is true that quite a few “Moon’s” are hollow and are Space Stations of sorts that are also remnants of “The Ancient Builder Race” (Who are either extinct from their warfare or negatively ascended). The ICC in coordination with the Draco Federation and other Human ET-Like Federations (Some deceptive Earth Breakaway Civilizations pretending to be “Star Being Federations”) have gained access to some of this information.
http://spherebeingalliance.com/faqs