Lord of the Rings: A World War I and II Allegory?

Nearly everyone agrees that J.R.R. Tolkien wrote a true masterpiece when he wrote his trilogy Lord of the Rings, and we find it surreal to think that he and other literary greats were able to create an entire world in their heads. This however is my question: what if the setting for the Lord of the Rings isn't a new world, but rather a twist on Europe during World War I, or World War II?

When the First World War started Tolkien was a student at Oxford University. After his graduation he joined the British Army and landed in France. While there he began to take record of what was happening and of the machines of modern warfare - machine guns, tanks, and poison gas. He was fighting in some of the bloodiest battles known to human history.

First, before I can give a detailed explanation a few things must be clarified:

1) Lord of the Rings was written in the 1930's and Tolkien was at war after graduating from Oxford in 1918. Therefore, it is quite feasible that the war influenced these stories.

2) This article is not saying that the Lord of the Rings is simply a retelling of the war; rather it is saying that the war helped create the map and basic scenario of the plot.

If we look at the map that Tolkien drew concerning his world then we would see that it looks a lot like Modern Europe without Italy. Mordor, the land of evil, is more or less in the location of Germany. Gondor, the land of the white city - the city of Kings, is in the location of France. And finally, the Shire, which is obviously England, is remotely north-left of everything. What happen to Rohan and the land of the elves? And how do we know that this is true? Throughout the books and movies there are given symbols to show us.