The BBC investigates Zhang Zhidong, also known as “Brother Wang”, a Chinese national described by US law enforcement as one of the most significant drug traffickers in the world.

He is now awaiting trial in the US and has pleaded not guilty. He is accused of building a criminal empire connecting China's chemical factories to the Mexican cartels flooding the US with fentanyl.

The BBC investigates his rise and fall, speaking to his former friend, and to cartel members who knew him as “number one” and the "king of fentanyl”.

Jordanian director Zain Duraie talks about her debut film Sink, an intense family drama about a mother coping with her son's mental health issues. Zain reveals the severe difficulties she faced to get the film financed, why she sought out the advice of other directors and how the film Titanic changed her life. And she offers her own tips for would-be film-makers. This episode of The Documentary, comes to you from In the Studio, exploring the processes of the world’s most creative people. If you’ve been affected by issues raised in this programme, you may want to speak to a health professional or an organisation that offers support.

The Atemoya Custard Apple is a much sought-after fruit grown only in one county in Taiwan. The Taiwanese are justly proud of it. Meanwhile, the Musang King Durian - grown in Malaysia - is also highly prized for its unique flavour as the ‘Hermes of Durians.’ Every year, fruit lovers across the region look out for these treats and snap them up where they can, often paying high prices. In recent years, farmers have seen opportunities to raise their income by selling these niche, super-luxury fruits on the Chinese market, but the strategy comes with big risks too. Koh Ewe from the BBC’s Singapore Bureau has been tracking the fortunes of these two fruits.

A statue of Saint Olga is a much-loved figure in Central Kyiv, Ukraine. So much so, that when Russia invaded Ukraine, the statue was given a flak jacket with the words “she needs armour” written on it. Saint Olga of Kyiv is celebrated by Ukrainians and Russians alike. She’s a saint in both the Catholic and Orthodox churches and her saint’s day is celebrated on 11th July. BBC Ukrainian’s Irena Taranyuk explores her sometimes violent history.

The Fifth Floor is at the heart of global storytelling on the BBC World Service, bringing you the best stories from journalists in the BBC's 43 language services. We're here to help you make sense of the stories making headlines around the world; to excite your curiosity and to get to grips with the facts.

Recent episodes have investigated Russia’s youth armies and how they make soldiers of Ukrainian children; featured the BBC team who were the first journalists to the site of the Nigerian school kidnappings and reflected the effects of internet blackouts in Iran, Uganda and India.

If you want to know more about Venezuela’s acting president, Delcy Rodriguez, and the legacy of Hugo Chavez; or how Vladimir Putin’s network of deep cover spies operates; or why Donald Trump signed an executive order granting white South Africans asylum in the US, we have all those stories and more.

This episode of The Documentary comes to you from The Fifth Floor, the show at the heart of global storytelling, with BBC journalists from all around the world. Presented by Faranak Amidi.

Produced by Laura Thomas, Caroline Ferguson and Hannah Dean.

(Photo: Faranak Amidi. Credit: Tricia Yourkevich)

In a summer of world class sporting events, tennis players have been battling it out at Wimbledon - one of the four major Grand Slam tournaments. One of the big stories has been the success of British wildcard entry Arthur Fery who, before Wimbledon, was ranked outside the top 100. His success has come with a big jump in prize money - essential to pay for the international travel, accommodation and coaches required to keep climbing the rankings. For those lower down the ranks, life on the professional circuit can be tough both emotionally and financially. Hamish Stewart, from Scotland, is currently ranked 300 and is all too aware of the personal demands of the job. "I've just missed an ex-college teammate of mine's wedding," says Stewart. He is joined by Jamie Loeb from the US, who is currently ranked outside the top 1,000. She had a career high of 132 and played in the US Open before injury and personal circumstances stalled her rise. We also hear from three coaches - Viktoria Belinsky, Noelle van Lottum and Michael Logarzo - who give us an insight into their jobs, the sport and its parallels with life.