Yes, you read that right — during World War I, British intelligence agents reportedly used semen as invisible ink to pass along secret messages. 🕵️♂️<br />While strange by today’s standards, this tactic was seen as innovative (and convenient) at the time.<br />Discover the weird world of spycraft history, where science and secrecy collided in the most unexpected ways.<br /><br />🔍 Like and follow for more weird history facts that’ll blow your mind!
