I can see many events and persons in LOTR that can be linked to events and persons in the Second World War.
- Saruman and his allies you can associate with Hitler and his allies.
- Saruman, just like Hitler, wants absolute power.
- Enormous amounts of weapons (or soldiers) are created and soldiers trained in LOTR before the war starts, just like happened in Germany before the war started.
- A super race (the Uruk-hai) is created, just like Hitler wanted to.
- The superweapon (the explosive destroying the wall at Helm's deep) compares to the V1 and V2.
- Hitler, as well as Saruman, want certain groups exterminated.
- Gandalf represents the leaders of the allied forces against Hitler.
- Gandalf, like the allied leaders, show respect for different cultures (though not for tyrants).
- Initally, the war was likely to be won by Saruman and allies.
- Hitler, like Saruman, shows no respect for Nature (apart from his dog).
- The war is ended if Frodo drops the ring in Mount Doom, Which destroys the tower with the all seeing eye completely, the like the dropping of the atomic bombs.
- The all seeing eye on top of the tower in Mordor can be compared to Hitlers SS.
- The "good" guys win.
- The true heroes are not the leaders, but the ones who execute the orders. American and Russian soldiers (I certainly omit a lot of them) can be compared to Sam and Frodo (in fact I think Sam is the biggest hero of both).
I'm sure I didn't mention a lot of other similarities, but I think 14 will suffice.