Livraria Lello - the bookshop that is said to have been an inspiration for JK Rowling, leading to... well, Harry Potter :D
The place is unbelievable crowded and one has to get a ticket just to get in! Good news is, you can redeem the ticket when you buy a book, which makes it a little better haha. This is the second floor of the place and I can definitely understand why the store has such a great reputation. It feels just like a room in Hogwarts.