People love to create time capsules as a way to speak to future generations – but the ugly secret is most time capsules are lost, vandalized, never buried or so poorly sealed that they dissolve before they're supposed to be opened.

Four men, calling themselves the International Time Capsule Society, have been trying for decades to educate people about best practices on how to create, preserve and remember time capsules. Many people haven’t been listening. Across the U.S., towns, civic groups, schools, businesses, special conferences...