When you are tired of looking at indoor and outdoor art along the Abandoibarra between Bilbao’s two world-class museums, go for a different vibe in Bilbao’s Old Town and Warehouse District.
On a weekday, you can browse the Mercado de la Ribera, one of the largest and oldest indoor markets in Spain. (I was there on a Sunday, but I did get to see some of the lovely stained glass windows in the guild hall.)
In the Warehouse District you will find the Alhondiga a multi-story public library built on pillars within an old warehouse, with a glass-bottomed swimming pool on the roof. It’s a wonderful re-imagining of how to use space. (Notice that no two of the supporting pillars are alike.)
In the Old Town are the usual medieval cathedral, narrow cobbled streets, and slightly skewed medieval buildings.
And if you explore the side streets, you will find some amazing, funky shops offering exotic (and painful-looking) piercings, gothic wear, and many other oddities.
If you want an overview, don’t omit visiting the park atop Mount Artxanda, the hilltop overlooking Bilbao, for a panorama which takes in both old and new Bilbao.
And then maybe you’ll want to take in the art scene just one more time before you leave.