A Coruña has one of the best coastal aquariums on this route — not a theme park, not a spectacle, but a genuinely well-curated window into the marine ecosystems of the Galician and Cantabrian coast. The touch pools and open ocean tank are the highlights. The location, right on the waterfront of the city port, means you can walk straight out of it and onto the harbor promenade.

Good for a morning slot, especially if the weather has not committed to anything yet.

Practical note: book online to avoid queues, particularly in summer.