If you want to see a wonderful view of the entire city, without being surrounded by people, this is the perfect place. It is also a very charming place, was a former anti-aircraft bunker during the Spanish Civil War, is pretty dilapidated but retains the essential structure.
A great place to find cool books and magazines. Maybe one of the best in barcelona. They also have a space for exhibitions that they often fill with amazing stuff.
Former headquarters of the "Textil Algodonera Foundation", an emblematic building of the XIX century of neoclassical style that is a reference in the city of Barcelona. They have an excellent restaurant where you can make a good brunch and a terrace ideal for summer evenings, I usually go to design when I need tranquility and that they treat me with professionalism, ideal also for an informal meeting or a drink with a good friend.