Soviet Union I believe was the southerners
They used Maginot Line. The Maginot Line was built to fulfill several purposes: To prevent a German surprise attack. ... To push Germany into an effort to circumvent via Switzerland or Belgium, and allow France to fight the next war off French soil to avoid a repeat of 1914–1918. To be used as a basis for a counter-offensive.
Answer:
Nile river?
Explantation: Its the only thing I could think of matching that statement
