
Solo, Bunkers del Carmel (Turó de la Rovira) is an easy yes.
Turó de la Rovira gives you a broad, unscripted view of Barcelona rather than a polished observation deck. The concrete platforms belong to a 1938 anti-aircraft battery, and the hill later became part of the informal Canons settlement, so the history matters as much as the skyline. It is exposed, short on facilities and markedly less pleasant when sunset crowds turn the summit into a photo queue.