When my wife and I recently celebrated our 25th anniversary, we were, of course, excited about the milestone, which only about two-fifths of American couples attain. But we were more excited about opening a cylindrical metal canister that we filled shortly after our wedding, which has remained untouched for the past quarter century.

We received the time capsule as a gift from my late mother, something that we did not even remember until we opened it. The capsule came with forms to fill out and instructions on things to insert, most of which were dutifully done by my wife. While I knew of the time capsule, and we discussed it often, with increasing frequency in recent years, neither my wife nor I remembered what was actually in it after all these years.