There are plenty of books on the subject, The 12th Planet by Zecharia Zitchin is one. However since this question was asked in clear sight of a google search, the author obviously prefers others to do his thinking for him.
In this regard perhaps one only need watch videos on You Tube such as Project Camelot interviews of such researchers as Richard Hoagland, Stewart Swerdlow, David Wilcock, Graham Hancock or Alex Collier.
If however one likes Hub Articles simple visit my profile and pick any number of my Hubs as they all pertain to ancient history and the lies we have been told for the last 10,000 years.
What most folks are unwilling to accept is that our ancestors were technologically and spiritually far more advanced than we are today and took their civilization back to Eden inside our Hollow Earth, where they reside today!
Aliens didn't build these testaments to time our ancestors did, what do think the Aurora Borealis really is, why do you think there is still a no fly zone over the poles 20 years after the Cold War ended, where do all the UFO's come from . . . right here . . . they never left.
Hollow Earth . . . The Greatest Kept Secret of All Time or is it?
World Wide Flooding or Polar Shift?