Straddling the banks of an estuary opening into the Bay of Biscay, Bilbao is the largest city in Spain’s northeastern Basque Country. Its earliest beginnings are preserved in the Casco Viejo, seven medieval streets that used to be guarded by walls. There visitors will find the city’s old churches, a large market, a public theater and the Academy of the Basque Language. Nearby sources of iron ore made Bilbao an important industrial and shipping center from the 14th century onward. The Spanish Civil War also started here. Today the city is being transformed by a growing service economy, and its prominence on the global traveler’s radar may be dated from the 1997 inauguration of the striking Frank Gehry-designed Guggenheim Museum Bilbao. In fact, the estuary town has become a veritable magnet for architects, boasting notable masterworks including Santiago Calatrava’s beautiful Zubizuri (“White Bridge” in Basque) and airport complex, the 541-foot Iberdrola Tower by the Argentine Cesar Pelli, a subway system by Norman Foster, the 1909 wine warehouse called Alhóndiga, converted a century later by designer Philippe Starck and the Euskalduna Conference Centre and Concert Hall by Federico Soriano and Dolores Palacios. The Zorrozuarre area is also being redeveloped, following a 2007 master plan by the Iraqi architect Zaha Hadid. For views of all of this, take the funicular from the city center to the top of Mt. Artxanda, where a sports complex, restaurants and a balcony await you.