The line is long this morning at this bank in southern Spain. An elderly lady stands at the front, sighing as she slowly fans herself with a pamphlet on savings accounts. Behind her, a mother and daughter loudly debate what to have for lunch. All of a sudden, the portly man in the back of the line breaks into song.

"To hold my own, I've had to pawn the parrot," he wails in Spanish, "I've even had to sell my house."

Singers accompany the flamenco dancers in the bank

A woman, dressed head-to-toe in black and wearing oversized black sunglasses, claps along as she moves to an empty space. Seconds later, she bursts into a flamenco performance, timed perfectly to the beat of his song.

Soon another seven dancers join in, heels clicking on the marble floor, filling the bank with sound.

Welcome to one of the ways Spaniards are expressing their frustrations with the economic crisis: flamenco flash mobs.

Turbo protest

For exactly four minutes, this group will bring business in this bank to a halt. As the customers' confused expressions turn to smiles, some clap along, others yell out a hearty 'bravo.' The bank's manager rushes over to the performers, asking them politely to leave, while signaling his employees to call police.

Brainchild of an anti-capitalist collective known as Flo6x8, these seemingly spontaneously performances have been taking place at banks across Spain. This morning the collective - which takes its name from a common flamenco rhythm - will perform in three banks, each exit carefully timed to avoid encounters with the police.

Financial institutions are a natural target for protesters in Spain

"Flamenco can be so forceful, so aggressive," says one of the dancers, who goes by the pseudonym La Nina Ninja, a play on the nickname for subprime loans.

Most days you'll find her in a downtown studio, patiently teaching the art of flamenco to students of all ages. But every now and then, she slips out of the studio to front one of these flamenco-infused protests. "It captures perfectly how we feel about the crisis. You can use it express desperation, rage, pain and the desire to change things."

Pseudonyms are necessary, she says, because the group's actions flirt with the law. While it's not illegal to stage a song-and-dance performance in a bank, the performers risk being charged with trespassing. And their insistence on recording and photographing each performance, despite protests from the bankers, could land them in court.

Flamenco and frustration

The idea of performing flamenco in banks came about when La Nina Ninja and a few friends noticed that two topics dominated all of their conversations: The economic crisis and their love of flamenco. "We decided to use flamenco as a common language to confront those responsible for this crisis," she says.

It was easier to channel her frustrations with the crisis into flamenco, she says, than to put it into words. "Flamenco is my way of expressing myself. When I have something important to say, I prefer to dance it rather than speak it."

La Nina Ninja, in black at the front, leads the dancers

The group's performances have been a hit in crisis-wracked Spain, with their videos earning more than a million views on YouTube and national media attention.

Public anger against the banks is palpable in Spain, says La Nina Ninja, as many blame them for irresponsible lending practices and for fueling the real estate bubble that collapsed in 2008. And at a time when one in four Spaniards is out of work, most banks have resisted the public's call for leniency on those who fall behind on mortgage payments. Instead banks in Spain carried out an average of 115 evictions a day last year.

Using flamenco to tell the stories behind these statistics is a natural fit, says one member who goes by the name Titi Mon Parne.

"Internationally flamenco is thought of as traditional Spanish music," he says. "But in reality it's always been more about giving voice to those on the margins of Spanish society."

Flamenco has its roots in the music of the Romani, a historically marginalized people

He points to Spain's turbulent history - from the civil war to nearly 40 years of dictatorship - when flamenco was used by social movements to speak out and fight for ordinary people. It's an art form for the "rest of us," he says, a tool of resistance against the dominant classes.

"We're fighting back against capitalism with our bodies," he says. "The body is an element that we all have; it's what makes us human. But capitalism on the other hand is totally the opposite. It's an arbitrary construction, one that's so far from anything that makes us human."

'Maddening poverty'

The ultimate goal of the flash mobs, say those behind Flo6x8, is to encourage Spaniards to use their voice to counter the crisis - in whatever form of expression suits them.

"Frankly, we're seeing things today that wouldn't be out of place in Spain 200 years ago," says Titi Mon Parne. "People picking through trash bins, looking for food and anything else they can use. The level of poverty is maddening."

And while many say Spain is turning a corner in the crisis, he disagrees. The situation is only getting worse, he says, warranting more action. "Tomorrow everyone in Spain might finally rise up and hold a revolution," he says. He pauses a few seconds before adding, "You never know."