Matthew Bevan

because there was no way for someone to go in and switch it on and off.

So they would assume that if they went through the building scanning for it, that they would be able to find it because there would be just a little tiny microphone hidden somewhere, constantly broadcasting anything it was picking up.

But they couldn't find it.

And also when they were wandering around inside the building, they could no longer hear the signal.

They couldn't hear the voices anymore.

You know, they're walking from room to room talking and the voices are not there.

And then they would leave.

And then a little while later, the voices would come back.

Oh, that's weird.

So somehow this device was switching on and off depending on whether it was being scanned for, which was a level of technology that the British and the Americans had no idea existed and couldn't fathom.

Well, yeah, so they first started hearing the voices in 1951, and it wasn't until 1952 that they managed to figure out what was going on.

They knew what frequency this thing was broadcasting on, right?

And when they walked through the building, they suddenly, if they were broadcasting that signal, they could also hear the voices coming through on their receiver.

So as long as they were broadcasting a signal and picking up signals...

They could pick it up and they gradually narrowed it down to a giant carving of the Great Seal of the United States, which was hanging on the wall of the ambassador's study in his residence.

They cracked it open sort of from the side, like two Oreos sort of cracking apart, if you can imagine that.

And inside, they found a device, a very simple device, which they called The Thing.

It had no power source and no electronic components.

and it just looked like a coin with an aerial sticking out of it, basically.

They were astounded by the simplicity and genius of this device.