The building where the library is now located was inaugurated in 1906. Special mention goes to its beautiful Art Nouveau façade with neo-Gothic details. On the inside, the library is decorated in painted plaster imitating wood and presents a magnificent staircase linking it to the upper floor - one of the first reinforced concrete works in Porto. Also worthy of attention is the huge stained-glass skylight, bearing the library's monogram and motto: 'Decus in Labore'. In 2008, the English newspaper The Guardian considered this library the world's third most beautiful, as did the Lonely Planet in its guide "Lonely Planet's Best in Travel 2011", describing it as an 'Art Nouveau gem', and particularly mentioning its 'neo-Gothic shelves' and the 'lolloping red staircase'.