When archaeologists find the foundations of a huge ancient structure (for example, the great ziggurat of Ur or the palace at Knossos), how do they know what the rest of it looked like?

by superkamiokande

This is what the ziggurat of Ur looked like after it was excavated, and this is what it looks like now, after having been reconstructed. This is a rendering of what it looked like complete.

How do we know these details about its structure? How do we know, for example, that there were little towers on top, and how do we know what those would have looked like? What kind of evidence is there for the structures that we don't actually see in the ruins themselves?

Searocksandtrees

hi! there are some archaeologists here, but for wider visibility you might consider x-posting this to other archaeology subs, /r/AskAnthropology, /r/AskScience (Social Sciences category), or /r/Archaeology