Lord Of The Rings: 10 Things You Didn't Know About The Elves
4. The Elven Bodies In The Dead Marshes Were Inspired By WW1
Tolkien had a remarkable life. As a young man he fought in WW1, serving in the Battle of the Somme, where he contracted trench fever and was required to return home to England. Despite Tolkien surviving the War, he was not untouched by it; he certainly saw combat on several occasions, and was horrified to learn that almost his entire battalion was wiped out after he left for England.
His experiences of trench warfare likely informed many aspects of his writing. Just look at any images of the battlefields of France; the torn and rent fields are not unlike Tolkien's description of Mordor. The realm of Sauron is described as fiery wasteland, of twisted rock. The barren plains are dotted with pits filled with toxic fumes - a clear reference to the shell holes that littered the battlefields of WW1, where poisoned gas would collect and linger.
Tolkien himself admitted that the images of dead soldiers left to rot in the mud, informed his notion of the Dead Marches: an area where thousands of elves were killed during the War of the Last Alliances, remaining there even until the time Frodo passed through.