What was the role of Micro-states in the 2nd World War?

What were the roles of the micro-states (The Vatican, San Marino, Andorra, Monaco, Liechtenstein, etc…) in the War? Were there any moments that these tiny countries made a huge impact on the world stage, or were they largely ignored?

I’ve been following your work for years now and it only ever gets better. I can’t wait to see were this series goes!