With the murder of Francisco Franco in 1975, Spain's oppressive dictatorship came to an end, and the counterculture that had been simmering away everywhere in Europe emerged with a boom.

"There was an enormous desire to do things after years of repression; people were desperate to express themselves," said Pepe Ribas, curator of Underground, an exhibition that commemorates the 1970s Barcelona counter-strong culture's but short blossoming.

Around 700 artefacts are on display in the Palau Robert, ranging from books, periodicals, and theater bills to Frank Zappa and the Rolling Stones concert posters, as well as black-and-white film from music festivals.

The exhibition's floor is covered with replicas of front pages from the time period, including coverage of Nixon's impeachment and John Lennon and Yoko Ono's wedding. Ribas said that embracing sex, drugs, and rock'n'roll was part of a larger counter-cultural movement that dated back to Allen Ginsberg and the Beat Poets of the 1950s and beyond.

"We wanted to resurrect all the libertarian movements – feminism, naturism, homosexuality, communes, cooperatives – that flourished in Catalonia between 1910 and 1930," said Ribas, who established the magazine Ajoblanco in 1974, which served as the house newspaper of Spanish counterculture for many years.

"We took to the streets to change the way we live and think," said one participant. We wanted to have sex, listen to new music, and study all we could about American counterculture."

According to Ribas, Barcelona had more independence than Madrid for a while since it was a backwater at the time, outside of the political process and with fewer people reliant on the state for their survival.

"For a time, there was a special freedom in Barcelona because the Franco regime concentrated its repression on political parties rather than people who wanted to change their way of life," he said.

"It was a period of incredible creativity, free of imposed norms, lived on the fringes of parties and institutions." The contradictions of the defunct Franco dictatorship, which targeted Marxist and pro-independence political groups for repression, contributed to Barcelona's geographical isolation from power centers.

All of this created gaps through which restless young people might smuggle themselves into countercultural organizations in other nations."

The show evokes the iconoclasm and pure pleasure of the period, as well as the feeling that Spain was re-entering the world after years of seclusion. There were feminist gatherings, dissident publications and cartoons emerged, the Stones played at the Monumental bullring in Barcelona, and King Crimson was only up the road in Badalona.

This golden era, however, was short-lived as optimism gave way to disappointment, as shown by a shift in drug culture from LSD to heroin's nihilism, according to Ribas. Spain was ravaged by a heroin pandemic by the early 1980s.

"Disenchantment set in at the end of 1978, partially because it became apparent that, although you might alter your everyday life, you couldn't change the institutions after the politicians had formed a deal with the franquistas over the democratic transition. We shifted our focus from ourselves to me."

Thousands of Ribas' contemporaries left the metropolis at the end of the 1970s "to be village schoolteachers and doctors and to live an alternative way of life in small villages in Menorca, the Pyrenees, and the Las Alpujarras in Andalucia," he stated when organizing the show. I was astounded at how many individuals from that period had managed to live their lives according to their values."

The fight for change did not go in vain. Spain has experienced remarkable transformations in the last 50 years, transitioning from a confessional to a secular state, and from a symbol of sexual repression to one of the first European nations to legalize same-sex marriage.

The roots of all this transformation, according to Ribas, were planted in a handful of alleyways off Barcelona's La Rambla in the mid-1970s.

Underground will be on display at the Palau Robert through November 28th. There is no charge for admission.

Thanks to Stephen Burgen at The Guardian whose reporting provided the original basis for this story.