Moonglow
Diamond Member
Annexation of ZaolziePolish attack against Czechoslovakia (an allie of Soviet Union) back in 1938. It was said to them in advance that Polish invasion in Czechoslovakia will means cancelling the Soviet-Polish non-aggression pact, and they ignored it. And, therefore, it was cancelled.
In 1938, Poland annexed the Czechoslovak region of Zaolzie, which was home to a Polish minority. The Munich Agreement validated this annexation