[CaptainHaplo]

6 is actually debatable - but I would have to go with Moscow for 2 reasons.

Had Russia lost Moscow, it would have forced Stalin to capitulate, or at the least reduced the Russian front to a mere sideshow.

However, more importantly, the failure to take Moscow is why Hitler took over total control over the army, leading to a number of disasterous decisions that allowed final victory. It also pissed off alot of his military generals, which led to some of the attempts on his life, as well as numerous other problems for him.

While Kursk is strategically important, one could argue that Stalingrad was more devastating to German fortunes.

Iwo Jima - though famous, was a small piece of the puzzle in the pacific. Though important, it did not have nearly the strategic impact that other battles did.

Midway is the runner up here. While it did open the door to the events that followed, and turned the tide of the pacific war when one considers the surface conflict - I have argued that even had the surface fleet remained defensive, the submarine force would still have been able to restrict the supplies to Japan. A loss at midway would have lengthened the war considerably, and created more hardship for submariners, but it was not the Aircraft Carrier that won the war. They may have gotten all the glory, but that is just one more reason subs have always been called - the Silent Service.