During the tour I told the story of the spies who were active in Rotterdam during World War I and handed out small pieces of charred parchment. At first glance, they appeared to be empty. But were they?
You might be feeling like an amateur spy right now, wondering how to make the hidden message appear. It can be tricky, and if you're having trouble getting the ink to reveal itself, you're not alone!
Here’s a little tip to help you out: the secret to reveal the message can be found on my socials.
Remember, this is no ordinary piece of paper — it’s part of the mystery and intrigue, just like the secretive world of espionage itself. So take your time, feel like a true spy, and let the hidden message unfold before your eyes.