User:MyNameIsNotBob/desk/Agartha

In 1692, the British astronomer Edmund Halley proposed that the earth was made of four concentric spheres. Halley expanded his theory to propose that the inside of the earth was lit by a luminous atmosphere. This hollow earth theory lay the foundations for a number of fiction writers to expand the idea into literary works.

In the 19th century, an eccentric war veteran, John Symmes, promoted his theory of a hollow earth, which was similar to Halley's model. Symmes requested to make a journey, along with 100 hundred men, to the north pole to discover the entry to the inside of the earth. In 1817, Symmes undertook his expedition, and returned without finding his proposed entry.

• http://www.t0.or.at/subrise/hollow.htm
• http://www.crystalinks.com/hollowearth.html
• http://www.ingentaconnect.com/content/bell/pgeo/2004/00000025/00000005/art00002
• http://olivercowdery.com/texts/1818symm.htm