I have my issues with Mr. Graham Hancock
1. He makes an assertion that stone age builders couldn't have built the pyramids and they just sprung up 5,000 years or more ago. This is inaccurate:
The old Kingdom Egyptians buried their kings beneath rectangular slabs called mastabas
one king decided to be buried under a series of masatbas and the step pyramid was born,
then the bent pyramid, then the red pyramid, then what they call the perfect pyramid;
all based on the concept of the mastaba, after which the Giza plateau was used to line up
the great pyramids.(to match the belt of Orion or to Egyptians Osirus)
2. He says no burial material was in the pyramid, again this is inaccurate; their was a built-in sarcophigus for king Kufu in a burial chamber inside the great pyramid
it was not used. Probably due to grave robbers, the pharoahs were buried thereafter in the valley of the kings.
3. Someone who writes of such things should actually see what is already common knowledge before running to ancient astronauts for help.
I do agree with the underwater complex in Japan, it is fascinating, I do believe in alien contact in ancient times and their inspiration of earlier humans, I do not like taking things that are there and pretending they're not, to further your own hypothesis.
Were aliens in Egypt? I think so and human time travellers as well, did they build the pyramids, no.