The original video posted was removed by Youtube so here is a related video that also talks of the remarkable insight Edgar Cayce had of the mystery of the pyramids and Sphinx ~
In a reading given by Edgar Cayce July 1, 1932 on the Great Pyramid and Sphinx – Edgar dated the Sphinx to be around 10,000 BC ~ The sleeping Prophet’s reply to questions 7 and 8 –
(Q) What was the date of the actual beginning and ending of the construction of the Great Pyramid?
(A) Was one hundred years in construction. Begun and completed in the period of Araaraart’s time, with Hermes and Ra.
8. (Q) What was the date B.C. of that period?
(A) 10,490 to 10,390 before the Prince entered into Egypt.
In a reading given by Edgar Cayce July 1, 1932 on the Great Pyramid and Sphinx – Edgar dated the Sphinx to be around 10,000 BC ~ The sleeping Prophet’s reply to questions 7 and 8 –
(Q) What was the date of the actual beginning and ending of the construction of the Great Pyramid?
(A) Was one hundred years in construction. Begun and completed in the period of Araaraart’s time, with Hermes and Ra.
8. (Q) What was the date B.C. of that period?
(A) 10,490 to 10,390 before the Prince entered into Egypt.
http://www.crystalinks.com/caycepyramid.html