A more thorough explanation:

Vestigium

Vestigium is an old-fashioned word that means a sign or trace left behind by a person or object. It can be a mark or impression that shows something was there before.

• The footprints in the sand were a vestigium of the person who had walked there before.
• The ruins of the ancient city were a vestigium of the civilization that once thrived there.

These examples show how vestigium can refer to physical traces left behind by people or objects. The footprints in the sand and the ruins of the city are both signs that something was there before, even though it may no longer be present.