In 1550 B.C., more than 1,200 years after the Great Pyramids were finished, ancient Egyptian pharaohs ... difficult to move and raise. But exactly how much did these obelisks weigh?

LEHNER: I'm an archaeologist and I study ancient ... an obelisk on a big barge. What do art historians who are also Egyptologists say about the extent that we can trust the way Egyptians show ...