An hour's drive takes us to Guernica. The market town of Guernica has a workaday feel — typical of this region, which is one of Spain's most industrial.

Visiting its stately parliament building you sense the importance of this town to Basque culture. Historically, leaders would gather in the shade of an old oak tree. And this new oak tree — supposedly a descendant of the original one — reminds the Basque people of their unique clan traditions.

In the adjacent assembly chamber, historic portraits of Basque lords surround today's representatives. And high above, a medieval lord swears allegiance to the almost sacred book of Basque laws.

In the next room, a stained glass ceiling causes Basque hearts to stir. A sage leader standing under that venerated oak tree holds the "Old Law," which provided structure to Basque society for centuries. Around him are groups representing the traditional Basque livelihoods: sailors and fishermen, miners and steelworkers, and farmers. And it's all set in a classic Basque landscape.

While it does have deep-cultural roots, most people know Guernica for a horrific event in the years leading up to World War II.

Guernica was bombed flat in 1937. Because it was long the symbolic heart of Basque separatism, the city was a natural target for the dictator Franco in the Spanish Civil War. His ally, Hitler, wanted a chance to try out his latest technology in aerial bombardment. The result: the infamous bombing raid that Picasso immortalized in his epic work, Guernica.

Picasso's mural, considered by many to be the greatest antiwar work of art ever, tells the story. It was market day. The town was filled with farmers from the countryside. First, a single German warplane bombed bridges and roads leading out of the town. Then, more planes arrived. Three hours of relentless saturation bombing followed. People running through the streets were strafed with machine-gun fire. By sunset, the planes had left, leaving thousands of casualties and Guernica in rubble.