It’s gotta be coins though.

Most famous example was Louis XIV who created medals specifically to preserve French history for future archaeologists.

At that time they realized that they knew almost everything about Romans and Greek through preserved medals.

So the King created a vast medal series (Histoire Métallique) intended to outlast paper, books, and buildings.

These bronze and gold medals were intentionally buried in the foundations of monuments like the Louvre, specifically waiting for future generations to excavate them.

So the key is: durable materials, widely spread.

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nntwozz an hour ago | parent [-]

If humanity suddenly died tomorrow the world would be littered with handy rectangular glass pieces all over the world.

Alien archeologists would have a field day figuring out what they were for.

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tdeck an hour ago | parent | next [-]

They're clearly a ceremonial artifact, and their reflective surface is used to perform some religious ritual or other, probably related to the sun.

	▲	jareklupinski an hour ago \| parent \| next [-]
		21st century humans had notoriously poor light receptors, so they used these "smart" devices to reflect more sun into their eyes in order to see while hunched over
	▲	hnthrow0287345 10 minutes ago \| parent \| prev [-]
		"They clearly stare into the black void to make themselves feel better!"

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Tade0 an hour ago | parent | prev [-]

Shame that dopant drift would render the chips inoperable eventually.

But if the Antikythera Mechanism is anything to go by, I think they would at least figure out it was an electronic communication device.