[Mr_Magoo]

The archaeologists, led by Dr Geoffrey Summers, found the Medes built their western capital, Pteria, on conquered land near the border of their empire. The metropolis was a huge citadel on a 5000ft mountain near what is now the Turkish town of Sorgun.

It had four miles of massive stone walls and hundreds of defensive towers. Seven monumental gateways and hundreds of buildings, including an imperial palace, have been found. But not one hole has been excavated. Dr Summers' team used remote sensing and geophysical survey techniques to map the metropolis to an accuracy of 10 centimetres.

Stupid question #46:
If no actual excavation has been done, how do they know it was a Capital city of the Medes? It could be anyone without evidence gathered during excavation of the site.

Along the same lines, without digging, how do they know it is an imperial palace there?

[blam]

I'll venture a guess:

Known history and surface artifacts.