Let’s see, the Soviet Union fell peacefully on Christmas Eve. The moment it fell people began to repair old churches, synagogues and monasteries. When Putin got wind of the people’s efforts he decided that all of the buildings that had been confiscated by the communists would be returned their original owners. Then he helped them to rebuild. Then he also helped them to build schools and seminaries.
It is quite possible that the “peace” that Mary promised was specific to Russia, which is separate from the final peace of the Immaculate Heart.
And the world will enjoy a period of peace.
Where is that period of world peace???