In her flat overlooking the main square of Dimitrovgrad, 90-year-old Maria Oteva casts her mind back more than seven decades to the foundation of the town in the early years of Bulgaria’s communist era.

“Back then, 50,000 volunteers built this city because they believed in something,” she says. “Nowadays, you wouldn’t find 50 people to come and clean up the dirty streets.”

All of this was made with our sweat – it was built by decent people who thought they believed in something Peter Sharkov

Oteva was one of those volunteers, aged 17 and eager to build a new socialist Bulgaria after the ravages of the second world war. She had joined the partisan resistance against the Nazi-allied government as a young teenager before joining the regular army in 1944 when Bulgaria, under Soviet occupation, switched sides. She operated a machine gun and then worked as a medic as the army fought its way into Hungary.

Left: Young volunteers during the construction of Dimitrovgrad; right: Maria Oteva today

Following the war, she joined the police force before being invited to join the “brigades” movement of volunteers being assembled by the new communist government for public works projects.

The most ambitious of these was Dimitrovgrad, a city that was to exemplify the brave new world being created. Its spacious streets, parks and imposing public buildings, constructed in “Stalin baroque” style, still stand today.

Q&A What is the Cities from Scratch series? Show Hide Scores of new cities are rising across the world from previously untouched desert and jungle, or on land “reclaimed” from the sea. While the history of cities built from scratch is long, the scale of the current epidemic is beyond anything seen before. Another 2.5 billion people are predicted to move to cities over the next 30 years and the trend shows no signs of stopping. New research has identified more than 100 examples, nearly all in Asia and Africa. This week Guardian Cities meets the 90-year-olds who built the Bulgarian city of Dimitrovgrad after the second world war (many still live there) and visits the bizarre Bahria Town development promising Karachi residents protection from terror attacks and violent crime. We look at Hong Kong’s plan to build artificial islands for 1.1 million people and examine Egypt’s dream to conquer the Sahara. We remember past visions of future cities and ask, is there ever a good reason to start a city from scratch? Nick Van Mead

Oteva was the leader of the first group of “brigadiers” to work on Dimitrovgrad, following a course of lessons in construction techniques. She lives in one of the original buildings constructed for workers in the city and spends much of the day on the balcony looking out over the town hall, watching life go by and children playing.

“I believed strongly in the ideas and perspectives offered by socialism,” Oteva says. “It gave people power and the keys to their future.”

A group of young volunteers pose during the construction of Dimitrovgrad

Dimitrovgrad was constructed on the site of three small villages, and named after the first communist leader of Bulgaria, Georgi Dimitrov, who would die two years after the city was founded. According to the regime’s official version of events, Dimitrovgrad was established on 10 May 1947 when a group of 40 young people arrived at the site on the banks of the Maritsa River on the Thracian Plain and decided to build the city of the future. It was to be a symbol of the conversion of a predominantly rural society to an industrialised, urban one.

The zeitgeist of that era is strikingly portrayed in murals at the Asen Zlatarov high school, the first built for the children of Dimitrovgrad’s workers. They depict the glory of workers striving to build a better country and future, with idealised communist images of family life, work, education and sport.

Left: Malamka Stoyanova, 82, a former teacher; right: Yordana Strancheva, 83, a former purse maker in one of Dimitrovgrad’s now-defunct factories

“Dimitrovgrad was very significant, it was the first of the grand communist projects, and they constructed a totally new city according to communist ideals of urbanism,” says Dimana Trankova, a writer who has authored a three-volume book on communist Bulgaria and written extensively about the city. “The project was very important in showcasing the new Bulgarian government.”

For some, the communist dream faded quickly. Penyo Penev, a poet, was an early and enthusiastic arrival in the city, and his works were promoted by the regime. But Penev killed himself aged 28, apparently disillusioned with the reality of life in the new utopia. His old apartment is one of the city’s few tourist attractions.

As Trankova points out, not everyone participating in the brigades was an enthusiastic participant. While many were already won over by the relentless communist message, some felt compelled to join to improve their standing with the new regime, having come from families that had fallen foul of it.

Clockwise from top: inhabitants and retired workers from the neighbourhood of Tolbuhin in downtown Dimitrovgrad; Peter Sharkov in his office; and Malin Dimovski, 85, part of the electrician brigade that took part in Dimitrovgrad’s construction

One of these was Peter Sharkov, now an 81-year-old author. Sharkov was born in a small village in south-west Bulgaria. When the communists came to power, his father’s land was seized by the government. Jobless and fearing imprisonment, the younger Sharkov travelled to Dimitrovgrad and enrolled as a brigade manager building housing units, despite his antipathy to communism.

“That time was good for poorer workers, who had the certainty of a decent living but it was a hard time for the wealthier families, who saw their property and land confiscated,” he says, adding that he still feels resentment about the communist period. Nonetheless, he feels a certain pride towards Dimitrovgrad.

“It’s important that the heritage is preserved,” he says. “All of this is made with our sweat. Everything has to be maintained – it was built by decent people who thought they believed in something. You can’t take that away from them.”

After the fall of communism, a large statute of Dimitrov was removed from the city centre, and now lies face-down in a corner of a park. Sharkov, like many others in the city, would like to see it reinstated.

Left: a mural in front of Dimitrovgrad city hall that glorifies the advent of communism in Bulgaria

Dimitrovgrad has made a rapid and incongruous transition to capitalist consumerism, says Trankova. Located at a crossroads near the Turkish border, the city developed a huge and lively market for previously unavailable goods, drawing shoppers and traders from around the region. Today, thousands come across the frontier to gamble in its gaudy casinos, which are illegal in Turkey.

Dimitrovgrad is also regarded as the birthplace of chalga, a pop-folk style of music that embraces the sort of vulgar lyrics and conspicuous consumption that would have shocked the early pioneers. Finally, the city was re-dedicated: its name now officially refers to St Demetrios, a saint popular in the region, rather than the late communist leader.

Ivo and Viktoriya with their son

For many younger residents, times have moved. Ivo Ivanov, 25, and his 27-year-old wife, Viktoriya, typify a generation that has no direct memory of the communist era.

'The next era of human progress': what lies behind the global new cities epidemic? Read more

The couple are worried about the country in which they are bringing up their three-year-old son, describing it as plagued by corruption and social injustice. A chemical factory originally named after Stalin employs about 1,000 people. This is a far cry from the days when it provided jobs for 10,000 workers and was the lifeblood of the local economy. The couple are preparing to move to the UK. Many of their friends are jobless.

“We have a better life than our parents did under communism,” says Ivanov. “We want to get rid of the label of ‘communist town’ and start building a future with the help of the EU and young people across Europe.”

Follow Guardian Cities on Twitter, Facebook and Instagram to join the discussion, catch up on our best stories or sign up for our weekly newsletter