Archaeology is often an accidental science. Many discoveries come to light as a result of modern construction, and archaeologists must race to recover as much as possible from these new sites before construction resumes and destroys the site forever.
Here is a story about a collection of clay tablets from the Assyrian Empire (about 3000 y/a) that are being deciphered. They reveal numerous mundane details about how the Assyrians managed their empire. We actually have a great wealth of written data from this ancient period in history because scribes typically wrote on clay tablets which are more durable than papyrus or paper.
