Frodo Baggins received a glimpse into a possible dangerous future by looking through the Mirror of Galadriel in The Lord of the Rings - but what exactly did he see? The scene took place in The Fellowship of the Ring, Peter Jackson's first film adaptation based on the novels by J.R.R. Tolkien.
The Mirror of Galadriel was a large silver basin filled with water from a nearby stream. The mystical object was located in the Elven realm of Lothlórien and powered by Galadriel (Cate Blanchett). Considered one of the most powerful Elves in Middle-earth, she and her husband, Lord Celeborn (Marton Csokas), were the rulers of the realm. Once Frodo and his fellow hobbits made it to Caras Galadhon, the central city of Lothlórien, Galadriel invited him to look into the magical mirror.
The Mirror of Galadriel granted the viewer a vision into their past, present, or possible future, albeit one shaped by what the viewer desired to see. When Frodo looked into the Mirror of Galadriel in The Fellowship of the Ring, he saw the Scouring of the Shire. The event was used to describe when a group of thugs raided the Shire and took the villagers hostage. The vision also revealed how the Shire was being destroyed by Saruman and an army of Orcs while Frodo, Sam, Merry, and Pippin chained by the ankles.
The Scouring of the Shire actually took place in the final book in The Lord of the Rings trilogy, The Return of the King. It doesn't directly occur in the movies but it was a warning used by the Mirror of Galadriel to reveal what would happen if Frodo didn't destroy the One Ring. After the horrific vision and a seeming intervention by Sauron, Frodo tried to pass off the Ring to Galadriel. She transformed to show Frodo how the One Ring would corrupt her if she kept it in her possession which proved why he needed to continue on his quest.
The Lord of the Rings scene featuring the Mirror of Galadriel played out a little differently in the books. In The Fellowship of the Ring, Frodo wasn't the only one invited to look into the mirror. Sam also got a glimpse into a future where his home in the Shire was dug up and his father was all alone. He also saw a vision of Frodo lying on a cliff which would come to be after destroying the One Ring in the future. When Frodo looked, he saw the Eye of Sauron and the ring weighed heavier around his neck. As in the films, he tried to give Galadriel the Ring but she resisted.
Despite showing different visions in the movie and the book, the Mirror of Galadriel served the same purpose in both tellings of The Lord of the Rings. Frodo learned that the destruction of One Ring was his responsibility and the fate of Middle-earth depended on his quest.