The National and University Library of Slovenia, also known as NUK, is a cool spot in Ljubljana. The most special thing about it is the building itself which was designed by architect Jože Plečnik himself. In fact, NUK is considered one of his best work. If you look closely, you will see that the windows were made in the shape of open library books and the walls include some of the bricks from the original palace that stood in this same place.