Final answer:
Russian troops occupied Berlin during World War II, which was a significant event leading to the end of the war in Europe.
Step-by-step explanation:
The major European city that Russian troops occupied was Berlin. This occupation occurred during the final stages of World War II. The Soviet forces entered Berlin in April 1945, leading to the eventual surrender of Germany. It marked a significant event in European history, ending the war in Europe and contributing to the defeat of Nazi Germany. The occupation of Berlin by Russia was a strategic military effort that led to a major Allied victory and the end of World War II in the European theater.