Archaeology is a destructive science—meaning that once a site is excavated, it is gone forever. ... For these reasons, archaeologists generally excavate only when there is a threat of destruction or when they may reveal vital information about past cultures. And they usually excavate only a small part of any site.

What is the purpose of archaeological excavation?

Excavations can be classified, from the point of view of their purpose, as planned, rescue, or accidental. Most important excavations are the result of a prepared plan—that is to say, their purpose is to locate buried evidence about an archaeological site.

Why do archeologists have to dig?

To get at the archaeological evidence, archaeologists dig through these layers of built-up soil and dirt to try to understand the processes through which the layers were built up over time, and to find any artefacts buried within the layers.