Biscay or Bizkaia, is a province of the Basque Autonomous Community, heir of the ancient Lordship of Biscay, lying on the south shore of the …Biscay or Bizkaia, is a province of the Basque Autonomous Community, heir of the ancient Lordship of Biscay, lying on the south shore of the eponymous bay. The capital and largest city is Bilbao. Biscay is one of the most renowned and prosperous provinces of Spain, historically a major trading hub in the Atlantic Ocean since medieval times and, later on, one of the largest industrial and financial centers of the Iberian Peninsula. Since the extensive deindustrialization that took place throughout the 1970s, the economy has come to rely more on the services sector.