Re: Was the Great Pyramid really a tomb?
No funerary evidence has ever been found there, and there is overwhelming evidence that the Egyptian civilization was heir to an even more ancient society. This view is rejected by mainstream archaologists for the simple reason that the implications would blow a real hole in most all accepted scientific theory of civilization and prehistoric timelines, and much would have to be rewritten and reassessed. Not many professional academics care to face the idea that all the Facts they've spent their lives (and fortunes in tuition) in acceptance of need some real overhauling.
The best explanation for the pyramids (and the entire Giza landscape, in fact) is that it was both an observatory and a precisely engineered reflection of the constellations of prime importance in the Egyptian cosmology.
There are almost certainly far more monuments buried in the region, and all of it together might well have some extremely important information for the future.
For excellent (and very readable) books on the subject, look for Graham Hancock, Robert Bauval and John Anthony West.