Recently I went to Egypt for a Nile Cruise holiday. The country is absolutely amazing, it's incredible to think that you are touching monuments and running your fingers over painted carvings more than 3.5 millennia old!
Above is a picture I took of the three pyramids which form part of the Giza site. The one in the middle is actually not the biggest (it's built on a raised part of the plateau) and was built for Khafre (Chephren). you can still see part of the cladding which originally covered the whole of the pyramid giving it a smooth surface.
The leftmost pyramid was build for Cheops (Khufu), this is the largest and I did manage to go inside (along with many other tourists, which rather spoilt the experience, no disrespect intended). I didn't exactly expect the thing to be completely hollow, but it seems a huge structure for such a small room!
The public gain access through a narrow shaft climbing at about 30°, in which you have to crouch as low as possible. This would be tricky enough if there weren't people coming the other way trying to get out!
I won't try to give you a complete page about Egypt or Egyptology as there are already plenty of sites available which do a good job, here is one of my favourites.