Photo posted on Twitter by @acampadasol, the organizing voice of the movement. 
Thousands of Spaniards angered by the country's high unemployment rate and politicians' perceived failure to address the crisis have mounted a protest camp in the heart of the Spanish capital, Madrid. The Twitter-fuelled, festive nature of the protests echoed the pro-democracy rallies that brought revolution to Egypt earlier this year.
Over 2,000 protesters packed Puerta del Sol square into the early hours of Thursday, bringing mattresses and sleeping bags and stretching a big canvas roof to protect themselves from the rain, much like in Egypt’s Tahrir square.
Protests were initially scheduled to take place only last Sunday, but hundreds decided to remain on the square day and night until regional and municipal elections are held on May 22. On the first evening police dispersed the protesters, but on Tuesday they let them say overnight – and they haven’t budged since. Similar overnight protesters, albeit smaller in size, were organised in several other cities, including Barcelona, Granada, and Sevilla.  
Protest in Madrid's Puerta del Sol on May 18, 2011. Video posted on YouTube by neovallense.
Post written with FRANCE 24 journalist Lorena Galliot.

“The protesters keep saying they are ‘indignant’, but they’re incapable of saying exactly what it is that they want”

Rafael Gonzalez is a Peruvian-born conservative blogger who has lived in Madrid for the past 11 years. He wrote about the Madrid protests on his blog.

This is a movement of the “ni-ni”:  a Spanish slang term for twenty- or thirty-somethings that are neither students, nor workers. I can understand their frustration: the unemployment rate for their age group is nearly 40%. Of course, if they focused more on working and less on going to the beach and holding ‘botellones’ [outdoor drinking parties]...
Nevertheless, I find it curious that they chose to vent their frustration in front of the Madrid district (which is led by a right-wing president) building. Why not the federal government building? I wouldn’t be surprised if they were manipulated by leftist parties. Or more likely: left-wing parties started the movement, but it has now completely escaped from their hands.
I went out to Puerta del Sol yesterday and spent a few hours talking to protesters. They struck me as utopic and vague. They kept saying they were ‘indignant’, but they’re incapable of saying what it is they want. And most of the demands they do have I find unrealistic: we can no-longer afford golden pensions, or a minimum retirement age of 61. I would like that, too, but it’s just not possible.”
In Granada, police dispersed an attempted sleep-in. Here, an elderly protester being removed from the protest site. "It's not just young people protesting", tweeted @DiCrEn.

"Organizers would say on Twitter ‘we need water and sandwiches’, and people came with stocks of food"

Javier Sanchez is a radio journalist in Madrid. He took part in the protests in the city’s Puerta del Sol in the night from Wednesday to Thursday.
This is a heartfelt, very spontaneous movement. It isn’t articulated around a single objective or ideology, nor is it led by a specific party; rather, people from all sorts of different political and social backgrounds came together for the same reason: we are sick and tired of the economic and political quagmire our country is in. [Spain's 21.3% unemployment rate is the highest in the EU - a record 4.9 million are jobless, many of them young people.]
Leaflet being passed around in the Puerta del Sol and on Twitter. Protesters are calling on citizens not to vote for either leading party in next Sunday's elections, and to cast a blank vote instead.

The anger came to a head last Sunday, during nationwide protests against the high unemployment rate. In Madrid, there were a few isolated incidents between protesters and police, and something snapped. The general feeling was: ‘if authorities won’t listen to us, we’ll stay in the street until they do’, and the word spread about camping out on Puerta del Sol. At first it was mostly students and young people, but gradually people of all ages and backgrounds joined too. Now protesters say they won’t leave until the elections on Sunday.
“It’s impossible to remove the protesters by force: the political fallout would be too serious”
The power of social media networks is such that before long, people came with sleeping bags, mattresses and plastic sheets to protect themselves from the rain. Organizers would issue a call on Twitter such as ‘we need water and sandwiches’, and more people came with stocks of food. People aren't leaving, on the contrary, more and more are coming. Tt’s just impossible to remove them by force at this point: the political fallout would be too serious.
Protesters sleeping in Puerta del sol on Wednesday, May 18. Photo @javiersanchez
The main question now is how to channel all this energy. In such a grass-roots, politically unaligned movement, there are bound to be diverging viewpoints. General assemblies have been held and citizen’s committee’s created to organize the movement and produce a list of concrete objectives, but it isn’t easy. I’d say there are two main trends: radical reformists, who are calling for a total upheaval and redesign of our political system - which I think is utopic –, and moderates, who want the existing political parties to take into account the protesters' main demands and concerns. People need to be able to make their voices heard in a real democracy: not just stick a piece of paper in a box once in a while and then the ruling party does whatever it wants for the next four years.”
Even the rain didn't scare away Puerta del Sol protesters. Photo @javiersanchez.
General Assembly on Puerta del Sol in the morning of the 19th. Photo @loasphx.

Madrid metro station 'Sol' re-named for the occasion... Photo @ofeTG