In modern times, it is not unusual for people to wonder what, if anything, will archeologists of the future (human or otherwise) will learn about our civilization from various artifacts we leave behind.
Some even take steps to preserve modern objects in a way that they're findable and interpretable tens of thousands of years in the future (e.g. nuclear waste warnings). In some ways, this might be considered a sophisticated form of geocaching or letterboxing.
Question: What is the earliest evidence of such 'preserve-objects-for-distant-future-discovery' behavior?
I am mostly curious about the earliest conception of the idea that civilizations have finite lifespans, are potentially discovered later, and that the inhabitants of such civilizations might be able to leave messages among the civilization ruins for future discoverers.