Mark Finnell

This is the voice of Matthew Bevan, the host of the ABC podcast If You're Listening.

The bombs dropped on Hiroshima and Nagasaki were the first atomic weapons ever used in war.

Almost 200,000 people were killed.

Japan surrendered soon after, bringing World War II to an end.

But while those bombs may have forced the conclusion of one conflict, they also supercharged the next, the Cold War.

You see, before those bombs in Hiroshima exploded... The Soviets still don't know about the bomb.

OK, so they're friendly but not friends.

But two days before Hiroshima was bombed, a group of Soviet children visited the US embassy in Moscow.

And they gave the ambassador there a very curious gift.

A hand-carved seal, the Great Seal, in fact, of the U.S.,

But if you look closely at it, very closely at it, you will notice something unusual about this particular seal.

A tiny hole, almost invisible to the naked eye.

Now, what is that doing there?

It's not a mistake by the Carver.

It's meant to be there.

But why?

Well, to understand that, you would have to fast forward to 1951, when the Cold War freeze between America and the Soviets is deepening.

And that is when that British radio surveillance operator I mentioned earlier is listening in to Soviet radio frequencies.

And they are especially concerned not just about what they're hearing, but who they're hearing it from.

Because it turns out that voice belongs to Alan G. Kirk, the US ambassador to the Soviet Union.