Don’t believe in time travel? For centuries, humans have found ways to speak to the people of the future without all those pesky wormholes in space. Rather they’ve stuffed sturdy vessels—time capsules, as we now know them—with letters, photographs and assorted ephemera, and buried them for subsequent generations to discover. Word has it that Paul Revere and Samuel Adams were the first Americans to create such a capsule in 1795.