Yes! Yes! Yes! That's it! Right!
Checkpoint Charlie is the name of the famous checkpoint in Berlin were US and Soviet tanks were facing each other waiting for the order to open fire. The thing that provoked this whole incident was the refusal of a western diplomat to show his passport to the GDR border guards when he wanted to enter eastern Berlin. Showing his passport, this diplomat stated, would mean a recognition of the GDR.
I think in the end they agreed on something silly, something like the diplomat had to show his passport but just through the closed window of his car, or something like that.
