King John’s Library, located at the University of Coimbra (oldest university in the country), in Coimbra, Portugal, is one of Portugal’s National Monuments. It’s a 300-year-old building that houses 55,000 books from the 18th century. It’s founder, King John V is prominently displayed at the library’s high altar.In Baroque style, the inside is all wood. A doorkeeper ensures the door of the library is locked at all times, and promptly as soon as visitors enter to keep humidity away. Interestingly, bats that live in the building help protect the books by eating insects and alerting through the noise they make changes in weather. Unfortunately, photography is not allowed inside the library. More information can be found at the University of Coimbra’s website.