So, we have been discussing these giants for a while...
but why does the Bible say there were giants IN THE EARTH? (Gen 6:4)

"And the LORD said unto Satan, Whence comest thou? Then Satan answered the LORD, and said, From going to and fro in the earth, and from walking up and down in it." Job 1:7

Does that seem a bit strange to anyone?
Searching various sites on the so-called "Hollow Earth Theory" revealed some interesting items. Of course, some of these sites get into the paranormal fringe areas, you know---the flying saucers and Bigfoot stuff, so please don't think I am trying to validate any or all of this material, but this old theory about the "Hollow Earth" is kind of interesting. I have linked a few of these below, explore them if you like. One thing I did not realize was the mention of this concept in other world religions, for example...

Buddhist Theory
"It is believed to be a race of supermen and superwomen who occasionally come to the surface to oversee the development of the human race. It is also believed that this subterranean world has millions of inhabitants and many cities, its capital being Shambala."

Hindu
"In India there is an ancient belief, still held by some, in a subterranean race of serpent people who dwell in the cities Patala and Bhogavati. According to the legend, they wage war on the kingdom of Agharta. "The Nagas," according to "The Deep Dwellers," "are described as a very advanced race or species, with a highly-developed technology. They also harbor a disdain for human beings, whom they are said to abduct, torture, interbreed with and even to eat."
http://www.crystalinks.com/hollowearth.html

Lots of interesting reading on this page, link at bottom...

ADMIRAL RICHARD E. BYRD
"The first public scientific evidence of Agartha's existence occurred in 1947 when Admiral Richard E. Byrd of the United States Navy flew to the North Pole. Instead of going over the pole - he actually entered the inner earth. In his diary, he tells of entering the hollow interior of the earth, along with others and traveling 17 miles over mountains, lakes, rivers, green vegetation, and animal life. He tells of seeing tremendous animals --resembling the mammoths of antiquity moving --through the brush. He eventually found cities and a thriving civilization. The external temperature was 74 degrees F..."

THE HOLLOW EARTH: A MADDENING THEORY THAT CAN'T BE DISPROVED
From OMNI Magazine (October 1983)...

United States Patent 1096102: The Hollow Earth Theory
"On November 25, 1912 Marshall B. Gardner of Aurora, Kane County, Illinois, USA, submitted his discovery application to the United States Patent Office. 18 months later, on May 12,1914, this federal agency granted Mr. Gardner United States patent 1096102, the second most important scientific document ever issued. Its scientific significance is exceeded only by the mechanical flight discovery of Orville and Wilbur Wright in 1903. For reasons which even Mr. Gardner could not have fully anticipated in the early 1900s, and which are now abundantly clear, his discovery soon became the most highly classified military secret of all time. In 1913 Gardner wrote his original book proving beyond any doubt that our Earth is a hollow sphere. So voluminous was the evidence which he continued to amass from studies of astronomy and Polar exploration, that he expanded his book to 450 pages in 1920...."
http://greyfalcon.us/Agartha.htm