Today is the anniversary of the massacre of civilians in the small town of Guernica.

On this day, April 26, 1937, Spanish cubist Pablo Picasso, who was living in Paris, worked on a painting with a familiar theme, the autobiographic subject of a painter and his model. The painting was commissioned by Spain’s Republican government in January 1937 while it was in the midst of a civil war with the rebellious Fascist-supported forces of General Francisco Franco. So far unsuccessful against Franco, Spain wanted art that could glorify Republicans. The obvious choice to do such art was the already-famous Picasso who accepted, a bit reluctantly at first, to paint a huge mural for the Spanish Pavilion at the 1937 Paris World’s Fair.

But on that very day, maybe unbeknownst to him at first, the Germans unleashed their relentless firepower on the civilians of Guernica in Spain’s Basque region. In Paris, these atrocities were widely reported, complete with graphic photographs. Picasso decided, maybe without hesitation, to switch his subject for the mural.

On May 1st, he began sketches for Guernica, now a widely known work of art that will always remind people of the ravages of war. Maybe inspired and driven by anguish, Picasso finished Guernica on June 4th, a short period for producing a work of art, especially of this size and importance.

Guernica, formerly at New York’s Museum of Modern Art for safekeeping, is now at the Museo National Centro de Arte Reina Sofia. I saw the painting there in a 2008 visit to Madrid.

The painting grabs your attention. Initially, because it covers the upper half of a wall 25 feet wide. Guernica is enormous, calculated to have impact. Picasso, also a gifted practitioner of classicist techniques, chose to paint Guernica in the abstract cubist manner in shades of black and white. You don’t see red splashes to indicate blood nor earth tones to show the setting.

Figures are stylized, their geometric forms defined by line instead of color. There is fragmentation — body parts are not always where you expect them to be.

A baby on the left edge of the picture — her eyes and mouth tightly shut in death —is the first thing you see as you inspect the picture. Her mother is grieving over her. Other figures are oriented in their direction. The baby and her mother form an image impossible to ignore. You get struck by her mother’s wide open mouth and you notice other figures, their mouths also open. They’re bound together in a silent, tortured, and collective cry. An agonizing cry, unheard and helpless.

Were Guernica done in a realist style, would viewers have quickly grasped its meaning and, in discomfort, also quickly turn away? But Picasso’s way (and reputation) make you look more closely.

You study details: Many victims are women and, perhaps because it was Market Day when the attack took place, there are animals (a horse with its body pierced, a bull, and a bird). Victims are mutilated (severed head bottom left); and old-fashioned weapons are useless (broken sword). The jumble of figures suggests chaos.

In black and white, with lines defining form, the painting is like a gigantic graphic illustration. In a pamphlet offered by the museum during our visit, Pablo Martinez interprets this as Picasso’s attempt to appeal more to the intellect, rather than emotions. Maybe.

For the painter as well as his audience, rationalizing (intellectualizing) is probably much easier than coping with an onslaught of very unpleasant emotions when encountering a disturbing event. Still, I can’t help thinking that Picasso, the consummate artist always in control of his process, must have thought that the fragmentation in cubist techniques (in this case, chopping body parts) suited his subject matter very well. The medium is almost the message.

The painting traveled widely after the Fair, raising money first for Republicans, then other anti-war efforts. Spain reclaimed it in 1981. Nearly a century later, when on the news, you often see the technology used in war, but rarely the victims of its inhumanity, Guernica still resonates loudly in a high-tech world of sanitized wars waged by remote control.

The looming specter of new wars has dashed the hopes of many for the world’s ability to extricate itself from a permanent state of war. We need a powerful painting like Guernica,to serve as an icon for the senseless, indiscriminate destructiveness of war.