Description
In 1917 in Fatima, Portugal, accompanying a miracle that was seen by 50,000 people, three young children, including Lucia de Jesus Santos, saw several apparitions of the Virgin Mary. One of the messages was a vivid vision of hell. Another of her messages of the Virgin was that the Pope needed to consecrate Russia to her Immaculate Heart, and then there would be a period of world peace and Russia would be converted. On the other hand, if there was no such consecration, then "Russia would spread her errors" and there would be war and persecution of the Church. The Pope issued several consecrations of the entire world to Mary's Immaculate Heart over the decades, and eventually Russia in particular was consecrated in 1952. Although there is still some controversy over whether the Pope fulfilled the specific conditions, Sister Lucia says that Russia was indeed consecrated in a valid way.
Source
"Fatima: A Grace For Mankind." Accessed 4 May 2014 <http://www.ewtn.com/fatima/>.
Mauriello, Matthew R. "Our Lady of Fatima." April 1999. Accessed 4 May 2014 <http://campus.udayton.edu/mary/meditations/Apr99.html>.