Yes i do believe that the earth we live in is hollow and there is another creatures or civilization there. I have read agartha it is a legendary city that is said to be located in the earths core, it is said that creatures living there are more in advance technology and food or fruits there has triple size than ours. It also said that the environment is abundant like a paradise.

The Hollow Earth is a pseudoscience concept proposing that the planet Earth either is entirely hollow or otherwise contains a substantial interior space. The scientific community has dismissed the notion since at least the late 18th century. The concept of a hollow Earth recurs many times in folklore and as the premise for subterranean fiction, and a subgenre of adventure fiction (Journey to the Center of the Earth, At the Earth's Core). It is also featured in some present-day pseudoscientific and conspiracy theories.

Contrary evidence
Seismic
The picture of the structure of the Earth that has been arrived at through the study of seismic waves[48] is quite different from the Hollow Earth hypothesis. The time it takes for seismic waves to travel through and around the Earth directly contradicts a hollow sphere. The evidence indicates that the Earth is filled with solid rock (mantle and crust), liquid nickel-iron alloy (outer core), and solid nickel-iron (inner core).[49]

Gravity
Another set of scientific arguments against a Hollow Earth or any hollow planet comes from gravity. Massive objects tend to clump together gravitationally, creating non-hollow spherical objects such as stars and planets. The solid sphere is the best way in which to minimize the gravitational potential energy of a physical object; having hollowness is unfavorable in the energetic sense. In addition, ordinary matter is not strong enough to support a hollow shape of planetary size against the force of gravity; a planet-sized hollow shell with the known, observed thickness of the Earth's crust would not be able to achieve hydrostatic equilibrium with its own mass and would collapse.

Density
Based upon the size of the Earth and the force of gravity on its surface, the average density of the planet Earth is 5.515 g/cm3, yet typical densities of surface rocks are only half that (about 2.75 g/cm3). If any significant portion of the Earth were hollow, the average density would be much lower than that of surface rocks. The only way for Earth to have the force of gravity that it does is for much more dense material to make up a large part of the interior. Nickel-iron alloy under the conditions expected in a non-hollow Earth would have densities ranging from about 10 to 13 g/cm3, which brings the average density of Earth to its observed value.