The photograph was taken in 1982, and the Queen is stood smiling at the camera with an abundantly filled bookcase behind her. Through the doorway, the selection of reading material continues, stretching across the walls of the vast room.
There is also a reading table and ornate chair, making it the perfect place for royals to enjoy a chapter or two.
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The caption reas: "Happy World Book Day! This photograph shows the Queen in the Royal Library at Windsor Castle in 1982. The Royal Library is a treasure trove of more than 50,000 books and manuscripts collected by British monarchs over the centuries."
The Queen has a very impressive room for reading
Royal enthusiasts were taken aback by this space with one writing: "I'd like to be the librarian there!" and another penned: "I would love to spend a week in the Royal Library just reading. Imagine how fantastic it would be to be a Royal Princess, you could spend your life reading your way through those books."
In another World Book Day post, this time shared by Buckingham Palace, the library of Balmoral Castle was revealed, and in this 1976 photograph, the Queen was accompanied by her husband, Prince Philip.
Balmoral Castle also has a large library
While the reading room in Scotland isn't quite as lavish as the one in England, it is still laden with plenty of books, as well as a colourful sofa which could be used for a more relaxed afternoon spent leafing the pages of a good read.
Her Majesty the Queen is living at Windsor Castle currently
Along with the photo of the couple, the Instagram post featured a painting of Queen Victoria and Prince Albert in the library at Windsor Castle, which showed the full grandeur of the impressive space in Windsor, and revealed that it also has a traditional fireplace.
The Queen is currently residing at Windsor Castle while The Duke is recovering from a procedure at St Bartholomew's Hospital.
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