This site offers a Quicktime video of the Pantheon. When asked,
click the "Test Drive" button to see it.
Current construction technology continues to adapt the dome structure to
suit various uses.
Think back to the
diagram of the stable arch. That construction worked because we
applied compression at the bottom so that the walls would not kick
outwards.
Now take
the next step: In your mind, spin the simple arch around its highest
point...what do you have? A dome!