How Was Were The Giant Pyramids Built?

This video shows the theory on how the giant pyramids at Giza (which I have been fortunate enough to see twice) were built.  It is a fascinating clip on the construction basically saying the outer portion was developed with a giant outside ramp (the same was used for the temple at Luxor) while inside tunnels were used to bring the smaller stones to the top levels.  I found it on Open Culture.  Here is part one of the  series.