Key crossing of WWII (5)

I believe the answer is:

rhine

(Other definitions for rhine that I've seen before include "Cologne's river" , "Bonn's river" , "fed by 8 [RHUR]" , "River rising in Alps, with mouth at Rotterdam" , "Ring river (Wagner)" .)

I've seen this clue in the Newsday.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.