This building has had quite a history having been a 12th century fortress, treasury, archives, royal residence, abandoned and almost demolished, to finally rise as a world class art museum . Various owners have added their touches over the years resulting in a succession of architectural styles and miles of corridors. Artworks covering 5 centuries fill the thousands of rooms. The geodesic pyramids were added in 1986 by Japanese architect I.M Pei to make an interesting entry feature. The most famous painting here is of course Da Vinci's Mona Lisa . The museum is so vast you should work out what you want to see first. Open every day except Tuesday, 9am-6pm, some opening times are free for students.