He was confined to his homeland for over four years by the Chinese authorities. When Ai Weiwei was finally allowed to leave China at the end of July 2015, he moved to Berlin to join his family. Beyond accepting the guest professorship at the Berlin University of the Arts (UdK) he had already been offered in 2011, the dissident artist's future plans were still open.

But it was clear to many that the famous Chinese provocateur wouldn't stop tackling political issues: "He's assumed his responsibility as a defender of human rights and I don't think that's about to change," museum curator Adrian Locke, who was preparing an Ai Weiwei exhibition at the Royal Academy in London in 2015, told DW at the time.

That same summer, an unforeseen flow of refugees was reaching Europe. The migrants' plight echoed Ai's own experiences; the dangerous journeys they undertook inspired a series of projects.

"With every exhibition, I also try to answer the question of who I am," the restless artist told the filmmakers of a DW documentary which followed him throughout that year, "Ai Weiwei Drifting."

Read more:Ai Weiwei's biggest installation to date is a giant refugee boat

Ai Weiwei's early 're-education'

Born in Beijing on August 28, 1957, Ai Weiwei experienced the bitter effects of totalitarian culture practically from the beginning of his life.

His father, the renowned poet Ai Qing, once close to Communist Party Chairman Mao, fell out of his favor in 1958. The Ai family was sent to a labor camp and spent time living in a pit dug in the ground.

Ai Weiwei was only one year old at the time. He grew up witnessing the humiliation suffered by his father, who was forced to clean the toilets of their village as a "re-education" measure.

The political climate cooled down with Mao Zedong's death in 1976 and the Ai family was allowed to return to Beijing.

Ai Weiwei then enrolled at the Beijing Film Academy at the age of 21. He lost interest in his studies, founded a radical artists' group called Stars, and participated in putting up posters critical of the regime on what became known as the Democracy Wall.

However, the young artist realized it was better for him to leave the country when the new Chinese leader Deng Xiaoping decided to crack down on the Democracy Wall movement, arresting its most prominent critic, Wei Jingsheng, in 1979.

From street portraitist to Biennale artist

Ai Weiwei landed in New York in 1981, where he enrolled at Parsons School of Design. Yet he preferred the burgeoning cultural life on the streets and in the galleries of the East Village to his art history classes, so he quit school.

Read more:Ai Weiwei provocatively poses as drowned Syrian refugee boy

He befriended Beat poet Allen Ginsberg and discovered the works of an artist who would deeply influence him: Marcel Duchamp. "After Duchamp, I realized that being an artist is more about a lifestyle and an attitude than producing some product," Ai once wrote.

In 1993, Ai Weiwei returned to his family in China. His artistic output became more provocative and his international career got a boost through Uli Sigg, an avid collector of Chinese art and Swiss ambassador to Beijing at the time.

Sigg hooked Ai up with the great curators of the art world. He was invited to the Biennale in Venice in 1999 and co-organized a show in China called "F*** Off" to protest the Shanghai Biennale in 2000. It was shut down by the police before its official end.

Pushing the boundaries of art

Even though Ai is not a trained architect, after designing his studio complex in Beijing, he ended up leading one of the most important architecture agencies in China, with his company FAKE Design. He was also hired as a design consultant on the famous Bird's Nest Stadium built for the 2008 Olympics in Beijing - but then became critical of the Games.

As an artist, he further pushed the boundaries of what can be considered art. When he was invited to the Documenta in 2007, the German contemporary art show held every five years in Kassel, he paid homage to the home city of the Brothers Grimm with an ambitious project called "Fairytale."

For his installation, he flew in 1,001 ordinary people from China. They lived in a dorm during the event and were asked to report on their impressions as tourists in Kassel.

In 2008, he challenged the Chinese government by launching a thorough investigation on the casualties of a deadly earthquake in Sichuan. His stubborn confrontations on this issue are believed to have exacerbated his problems with the authorities: He was arrested and beaten by the police in 2009.

Read more:Ai Weiwei plans Berlin memorial to drowned refugees

The police beatings led to brain hemorrhage. The artist was hospitalized in Munich, while setting up his exhibition "So Sorry" at the Haus der Kunst.

Arrest and travel ban

In 2011, Ai Weiwei was arrested at the Beijing airport and detained for 81 days in a secret prison. After being released on June 22, he was not allowed to leave China for the following four years; his passport was confiscated.

During that period, support for his case was widespread in Germany. Gallery owner Alexander Ochs and a group of Berlin friends initiated an appeal at the time: "Freedom for Ai Weiwei," signed by thousands of people in the country, was later followed by a second initiative, "Passport for Ai Weiwei."

Despite not being allowed to travel, Ai managed to organize his largest one-man exhibition in Berlin's Martin-Gropius-Bau. Some of the installations were specially designed for the museum, although he could not set foot in it himself.

Still, his strong sense of architecture allowed him to provide "a perfect plan," the curator of the exhibition Gereon Sievernich told DW. 

Berlin loves Ai Weiwei

As the director of a movie called "Berlin, I Love You" (2015), Ai Weiwei certainly has strong ties with the German capital. The short film depicts his long-distance relationship with his six-year-old son, Ai Lao, who had already been living there with his mother for nearly a year before Ai joined them at the end July 2015 when his passport was finally returned.

The artist directed his ode to the German capital from Beijing, via Skype. Comparing the city to New York in the 1980s, or Beijing, Ai enjoys the unfinished feel of Berlin, the fact that it still has "empty rooms." That's why he feels at home there.

From surveillance to digital transparency

Until 2005, Ai Weiwei had barely used a computer. However, he has since turned into an avid social media user, proactively putting his own life under "surveillance" - or at least making it transparent. He would comment on the Chinese authorities through his blogs, which were repeatedly closed down.

He now posts several photos a day on Instagram, which usually all get several thousands of likes.

He explained that he does that "because life is short and transitory," pointing out that he could've died from his hemorrhage in 2009 or still be detained in China. "I can't bank on having a long life ... that's why I want to record it."

A few days after his 60th birthday, Ai Weiwei will be celebrating the September 1 world premiere of his documentary "Human Flow," competing at the Venice Film Festival. The documentary about the global refugee issue was filmed in 23 countries over a year and will be released by Amazon this fall.