But by and large, you would, in the broad scope, be able to put the Empire State Building and Manhattan in an overall context of development here in the United States and in the modern 19th and 20th centuries.And you would know that it didn't date, for example, to the colonial period of George Washington and Thomas Jefferson, because nothing you'd find in the Empire State Building ruins, around it, in the dirt surrounding it—maybe it's a stump sticking up above the sloping ruins of Manhattan—nothing really looks like the flowing blue china, or the other kinds of utensils and material culture that they used in the time of the American Revolution.
For example, the great boat that was found just south of the Great Pyramid, which we think belongs to Khufu, that was radiocarbon dated—coming out about 2,600 B. NOVA: But how do you carbon date the pyramids themselves when they're made out of stone, an inorganic material?
LEHNER: We had the idea some years back to radiocarbon date the pyramids directly.
We find the bones of the people who lived and were buried in these tombs. But primarily we date the pyramids by their position in the development of Egyptian architecture and material culture over the broad sweep of 3,000 years.
So we're not dealing with any one foothold of factual knowledge at Giza itself.
So it's hard to give a succinct answer to that question, because we date things in archaeology on the basis of its context and a broad mass of information and material culture—things that were used by people, styles, and so on.