The Olympic Games has a problem. In recent years the number of cities entering bids to host either the Winter or Summer Olympics has dropped dramatically. For the 2004 Summer Olympics, 12 cities bid. For the 2024 summer Games, there are only four cities running.

The 2022 Winter Olympics bidding cycle saw just two cities compete - winners Beijing, China and Almaty, Kazakhstan - after the other five cities that expressed an interest pulled out due to public and political opposition. And in cities that are hosting, the Olympics has been met with hostility.

Protesters tried to put out the Olympic torch in Rio, and in Tokyo public outcry at the cost of the stadium for 2020 has led to a complete redesign. Four expert witnesses pin-point exactly what is putting off potential host cities and discuss radical solutions.

(Image 'No Boston Olympics' permission from Liam Kerr and Chris Dempsey)

The fighting in Ukraine has fallen off the front pages recently after making headline news in 2014. But Ukrainian forces and Russian-backed separatists are still engaged in a frozen conflict with no military or diplomatic solution in sight. Soldiers, rebels and civilians are dying. It looks good for Russia. Ukraine lacks the military power and international support to take back the East of the country where Russian-backed separatists hold huge swathes of land. And President Putin’s approval ratings at home have soared thanks to his annexation of Crimea in 2014. But does this mean Russia has won in Ukraine?

Presenter: Helena Merriman

(Photo: Separatist soldiers stand on a military vehicle during a city celebration on September 14, 2014 in Lugansk, Ukraine. Credit to Getty Images)

On 30 June this year, a study was released in one of the world's top scientific journals. It explained how a group of scientists who had been measuring the amount of ozone in the stratosphere had made a startling observation - the hole in the ozone layer had shrunk. Here, they said, was the first, clear evidence that the ozone layer had begun to heal. So how did this happen? It is a story that involves dogged scientific endeavour, the burgeoning green movement of the 1980s and the signing of what has been described as the most successful treaty ever created.

(Photo: Severe thinning of Earth's protective ozone layer found over Antarctica, by Nasa scientists. Credit: Getty Images)

After more than 50 years of armed conflict that has left 200,000 dead and millions displaced, Colombia is on the brink of peace. A final deal between the government and the Farc guerrilla movement is expected to be signed soon. Thousands of armed fighters will then lay down their weapons in preparation for reintegration into a society from which they have been estranged for years. But the process will not be easy – for the Farc’s fighters, or for the rest of Colombian society.

(Photo: Fighters of the Front 53, a faction of the leftist Revolutionary Armed Forces of Colombia (Farc) guerrilla movement, in Los Alpes, 150km south-east of Bogota. Credit: Getty Images)

“Brexit means Brexit,” says Theresa May, Britain’s new prime minister. It sounds pretty unequivocal: the UK voted in a referendum to leave the European Union, so that’s what it must do. But credible figures from US Secretary of State John Kerry to former prime minister Tony Blair have suggested that Brexit may not actually happen. Is that – legally, politically, democratically – possible? The Inquiry has the answer.

Presenter: Maria Margaronis

(Photo: Illustration flags of the European Union and the Union flag sit on top of a sand castle on a beach in Southport, United Kingdom. Credit to Getty images)

Donald Trump has shocked the US political establishment by knocking out every other Republican candidate to become his party’s presumptive candidate for President. Does he have a realistic shot of taking the White House? His campaign is short of money and some senior Republicans are refusing to endorse him. Current polls suggest his chances are slim. But his message has found an audience other politicians have failed to reach – he has become a lightning rod for many disaffected Americans. So, our question this week, can Trump win? Presenter: Helena Merriman

(Photo: Donald Trump, presidential candidate 2016. Credit: Getty Images)

The $5bn settlement recently agreed by Goldman Sachs is the latest in a long list of multi-billion dollar fines paid by banks implicated in the 2008 financial crisis. But behind these giant corporations are individual bankers, taking everyday decisions. It is those decisions which really matter. If you could find a way to nudge bankers towards better and safer choices, building a culture of integrity, you might avoid future financial trouble. But can you make bankers behave better? Taking evidence from witnesses including a Goldman Sachs insider and a regulator deploying psychologists in banks, The Inquiry looks for an answer.

(Photo Montage: Bankers/Stock market charts/City of London. Credit to Getty)

The UK has voted to leave the EU, sending shockwaves through Britain’s political class and its economy. Whatever the fate of Britain – and many fear years of damaging instability – Brexit is a serious blow to the European Union. Britain is far from the only member state with doubts about the scope of the European project. There are strong Eurosceptic movements in many other nations too. Some think the British precedent will boost their influence or that other nations will be able to use the threat of exit to undermine shared decision-making. And the loss of Britain – which is still, for now, Europe’s second-largest economy – could leave the Union precariously unbalanced, with Germany too dominant within it. As the EU contemplates an uncertain future, we are asking whether the EU even has a future without the United Kingdom. Presented by Chris Bowlby.

(Photo: David Cameron, Chancellor Angela Merkel, Bulgarian Prime minister Roesen Plevneliev, Eurozone finance ministers with bank notes, euro coins and a map of Europe in the background. Credit: Getty Images)

Hillary Clinton is the odds-on favourite to be the next president of the USA. But polls show more and more Americans view her unfavourably. In fact, the public's hostility towards her is record-breaking. Only Donald Trump elicits greater antipathy. That’s perhaps less surprising. He is a political outsider, and a divisive figure. But why does Hillary Clinton - a mainstream, centrist politician - provoke such strong, negative feelings? Presenter: Helena Merriman

(Image: Montage of Democratic presidential candidate Hillary Clinton with a sign 'Hillary You Liar')

“More than half the people of the world are living in conditions approaching misery,” declared President Truman at his second inauguration. “For the first time in history, humanity possesses the knowledge and skill to relieve the suffering of these people.” That was 1949.

It is a claim we have heard many times since - that ending poverty is within our grasp. But it is a dream which has - despite decades of effort - eluded us. Now the United Nations has set a new target - to eradicate extreme poverty by 2030. Will it be different this time?

We have already come a long way. For the first time in history fewer than 1 in 10 people are poor around the world. A billion people have been lifted out of extreme poverty since 1990. But achieving the UN's new goal means reaching another 836 million people in the next 14 years. And that will be tough.

Are we really about to end world poverty? Our experts include an economics professor who was himself born into poverty in China, and Helen Clark, who hopes to be the next leader of the United Nations.

Some 92% of married Egyptian women aged between 15-49 have had their genitals cut. FGM is more common in Egypt than anywhere else in the world. These astonishing statistics are all the more surprising when you consider that Egypt banned the practise in 2008. So why is FGM so prevalent in Egypt? Four expert witnesses tell us about the challenge of turning a widely-followed tradition into a crime.

(Photo: A gynaecologist co-operating with the Coptic Center for Training and Development gives a lecture on Female Genital Mutilation (FGM) in a village close to Beni Sueif, south of Cairo. Credit: Getty Images)

The World Health Organisation says the number of cancer cases will rise by 70% over the next 20 years. A huge amount of effort and money is spent fighting the disease. But are we getting that fight right? In this special hour-long edition of The Inquiry four expert witnesses tell us new ideas are being stifled, that there is not enough money being spent on drugs to treat early-stage cancer and that we are not doing enough to stop people from getting cancer in the first place. We put that evidence to someone in a position to do something about it - Dr Francis Collins, director of the US National Institutes of Health, the world's largest biomedical research agency, with a budget of $32 billion.

(Photo: Lab Technician preparing protein. Credit: Reuters)