Of David H. Lewis - from New Jersey, USA, who has spent countless years studying ancient transcripts, hieroglyphics, etc

Advanced Ancient Civilizations - Results of the LAH Expeditions 2004-2011 English subtitles;

Preface: the author here claims that a unknown, secret entrance to the great pyramid was at last found on the basis of instructions and "intricate codes" - found in a type of underearth tomb in 1936. These code-findings were east of Athena but the "statements" was not correct decoded until many years later he claims. Yes - it was not before june-76 that a small group was able to enter these enormous underground chambers lying deep under the pyramids on Giza.
They claim to have taken thousands of microfilms of what they found - things that proves far distant ET-visitations, underground civilizations and far developed societies on earth. It may seem as a fantastic claim or a big bluff - but remember that if this should be true - the conservative scientific society and the might-powers in position - would do all to hide or stop these things from being revealed. This is not groundless claims - because the now released reports from "the disclosure project" - shows very clear what the men in power has so well covered and denied ET-visitations and similar the last 60 years or more.
Another might power that try to prevent these discoveries to come forth, is the mighty churches and the western religions - and the author here was also strong influenced of this - as most of the Americans seems to be in many ways. He was a son of a priest (Rev..)
Their might would weaken a lot - if proven discoveries would show that "god" did not make/create earth - and humans, as said literally in  the bible, some few millenniums ago.
Another thing to remark, like some spiritual sources say - is that so-called evidence - that is too convincing - is not allowed to come forth from the spiritual "controlplane"!! BECAUSE EVIDENCE IS SOMETHING THE RIPE SEEKER MUST AND WILL  RECOGNIZE INSIDE HIM/HERSELF when he/she is mature. Therefore it is to consider, that like in this case,  "the society"  was not yet mature for this to come forth - until time is right.
It is also interesting that other sources as Lobsang Rampa and some physical ET- contactpersons, told similar things that the claims here says.
(Some words are translated and some headlines added. There may be wordmistakes - as text is scanned).
Here some from the epilogue first:"This unusual venture into these secret chambers was costly, not only in a monetary aspect, but in the four lives that were lost in the few short years that followed the expedition - due to this entry and the information gained. Although nothing was removed from these chambers, the microfilms have since proven to be a priceless entity to those who place money in a higher regard than human life. It is entirely doubtful now that these microfilm clips will ever be displayed for the general public and will remain as guarded as the spacecraft now in captivity at our Air Force Base.
"The records within this tomb are as near endless as time itself and had all these discs and plates been photographed, instead of the mere 2,700 that were taken, we may now have been able to conquer the many fears that befall every man. We may have gained enough basic knowledge to now prolong our total demise, changed the lifestyle of all those on earth, prevented the massive starvation now engulfing the world, found cures for cancer and other ills that plague mankind and eventual accomplished a new race of greedless people. Had we dug deeper with more photographs, we may have discovered the secret of the anti-gravitational machine, perfected the laser for our new and improved society, accomplished terrestrial travel, produced tiny wafers that would supply a multitude with the proper nutrition thus preventing hunger among the needy, and last but far from least, we may have found a sound use for telekinesis and teleportation.
What you have read in these preceding pages is not only the basic truths of the expedition, but only a brief scanning of the overall data retrieved. Since our Pyramid is evidence of our past - and can never be duplicated, we can actually say that Noah's Ark, the UFO's and Atlantis fit this same category of the higher technologies of the once advanced civilizations who inhabited our earth. Therefore, if these basic truths are now visible, how could one deny the contents of this tomb or the fact that such a tomb exists. It is not all that difficult to imagine the technologies of our ancients - in a comparison to ours. Their advancement was based on supreme knowledge handed down for millions of years - while our advancement is based on the bodies we must tramp upon to gain just a minor degree of advancement.

So from chapter 4-PASSAGE TO THE TOMB