Before planning our little excursion, the breadth of my knowledge regarding Bilbao, Spain could be summarized in three words: The Bilbao Guggenheim. Strangely, my first impressions of this building were from my calculus book during college (image link coming soon). The architect, 
Frank Gehry, utilized a calculus based software package, CATIA, to match the tagents and control the parametric surfaces of the curving planes of the edifice. The result: an amazingly effecitve use of implied motion in a functional building. As the image at the top of the page (exterior) and the image to the right (interior) suggest, the Bilbao Guggenheim's external compexity is merely a prelude to the complexity found within.Of course, Bilbao has more history than just the Guggenheim. At the turn of the 20th century, Bilbao's extensive industrial capability made it one of the wealthiest cities in Spain. Later, as industry declined, Bilbao made concerted efforts to reinvent itself as a tourist destination. For more info, follow the link above.