Proton beam therapy is the one of the most technologically advanced though expensive cancer treatments in the world - but it has the potential to save the lives of children with otherwise incurable cancers.

Over two years, Horizon follows the engineers, scientists and medics as they race to build two new centres, one at the Christie Hospital in Manchester and one at University College Hospital in London, as well as following as the first children awaiting the lifesaving treatment. This is one of the most complex challenges the NHS has ever attempted.

At the cutting edge of particle physics, proton beam therapy involves splitting hydrogen atoms to create a beam of protons travelling at two-thirds the speed of light, which target tumours with millimetre precision. But doing this in the heart of two of our biggest cities is no easy feat. The process generates so much radiation it needs to be housed in a maze-like nuclear bunker, with walls four metres thick. 2,000 tonnes of precision instruments are installed - more than four jumbo jets worth - and it all has to work perfectly.

This special BBC Two programme goes behind the scenes on the £250 million cancer cure - from digging the biggest, widest hole ever to exist
in London to the treatment of the first patients in the UK.

The 2018 SXSW Audience Award-winning feature film debut by Gabriel Silverman and Fiona Dawson, TransMilitary follows the Emmy-nominated short film Transgender, at War and in Love. Around 15,500 transgender people serve in the U.S. military (notably the largest transgender employer in the U.S.), where they must conceal their gender identity because military policies ban their service. TransMilitary chronicles the lives of four individuals (Senior Airman Logan Ireland, Corporal Laila Villanueva, Captain Jennifer Peace and First Lieutenant El Cook) defending their country's freedom while fighting for their own. They put their careers and their families' livelihoods on the line by coming out as transgender to top brass officials in the Pentagon in hopes of attaining the equal right to serve. The ban was lifted in 2016, but with President Trump now trying to reinstate it, their futures hang in the balance again.

Using interviews filmed over four years, Noam Chomsky discusses the deliberate concentration of wealth and power found in the hands of a select few.

120,000 Japanese Americans, born free and equal, were stripped of their basic human rights and imprisoned during WWII without any judicial procedures. Survivor George Takei and generations of families explore the campsite in Manzanar and Tule Lake and reveal their stories of trauma and scars of history as it is repeating itself again in the US. With breathtaking photography of Ansel Adams who documented the lives of the people behind barbed wire, the challenge of American ideal and reality are revealed.

According to a 2016 Johns Hopkins study, more than 250,000 people in the United States die from medical error every year, making it the third leading cause of death in the country. HBO documentary, "Bleed Out," examines the harsh reality of medical errors. Telling the story of Judie who took a fall in Nov. 2009, following a hip replacement earlier that year. It was just a partial hip replacement. But a few short months later, Judie was in a coma with permanent brain damage.

This documentary looks at the factors that led to the 2008 financial crisis and the efforts made by then Treasury Secretary Henry Paulson, Federal Reserve Bank of New York President Timothy Geithner, and Federal Reserve Chair Ben Bernanke to save the United States from an economic collapse.

A documentary that declares the gas industry's portrayal of natural gas as a clean and safe alternative to oil is a myth, and that fracked wells inevitably leak over time, contaminating water and air, hurting families, and endangering the earth's climate with the potent greenhouse gas methane.

When Josh Fox receives a $100,000 offer from a natural gas company interested in exploring in his land in Pennsylvania's Delaware River Basin, he decides to do his own research on drilling and the process known as fracking. Josh sets out to interview those who live near drilling sites, and his findings are frightening -- their wells contaminated, residents can actually set their tap water on fire. Visits to sites in Colorado, Wyoming and Texas yield similar horrific findings.

The heart-stopping story of 'Crazy Fakhir', a Kurdish colonel in the Iraqi army and legendary bomb disposal expert who single-handedly disarmed thousands of landmines across the country with just a pocket knife and a pair of wire clippers.

Between the fall of Saddam Hussein in 2003 and the chaos and destruction wreaked by IS ten years later, Fahkir's unwavering bravery saved thousands of lives throughout Iraq. 'Hurt Locker Hero' tells Fakhir's story through the raw and visceral amateur footage captured by his soldiers on a camcorder intended for filming family occasions. Instead, it records Fakhir endlessly snipping wires, searching family homes and digging out roadside IEDs, insisting it's too dangerous to wait hours for the highly trained American bomb disposal teams to arrive.

Whilst their father and husband becomes a hero, Fahkir's wife and eight children struggle to make ends meet and worry endlessly about his safety. Fakhir will be remembered as the man who risked his life to save others -'If I fail, only I die, but if I succeed, I can save hundreds of people.'.

Louis Theroux heads to California, the US adoption capital, where the majority of newborn adoptions are carried out privately, creating a multimillion dollar industry. Agencies, facilitators and lawyers can earn thousands of dollars per baby by matching up pregnant women prepared to give up their newborns with adoptive parents willing to pay up to $50,000 for the privilege.

Louis spends time with the birth mothers preparing to hand over their own flesh and blood, uncovering the stories of poverty, addiction and abuse that can push these women into making such a heartbreaking decision.

He also meets the adoptive families, paying out huge amounts of money in the hope of being able to raise a child they can't have by natural means - but in a system open to abuse, whether the birth mum hands over the baby hangs in the balance until after the birth.

In the US, there are now six states that offer the terminally ill the option of ending their lives with a prescribed cocktail of drugs.

Louis heads to California, one of the latest states to adopt this law, where residents can now take home a lethal overdose as long as they are terminally ill, of sound mind and strong enough to administer their own prescribed dose.

Here, Louis is invited into the family homes of those who want control over ending their own lives. But he discovers that when you have complete autonomy over your own death, choosing the right time is not such a simple decision.

Louis also meets a group who provide information about how to die to those who don't fit the legal criteria. With them, he meets a woman planning to end her life long before what would appear to be her natural time, raising complex moral and legal questions about how much control we should have over our own deaths.

For hundreds of years, romantic relationships in western society have been based on the idea of monogamy: two people, together, for ever. But with nearly half of all US marriages ending in divorce, perhaps the traditional model is no longer fit for purpose.

In Love Without Limits, Louis travels to Portland, Oregon, the heart of a movement seeking to rewrite the rulebook on how we conduct intimate relationships and experience family life.

Portland, whose city motto is 'Keep Portland Weird', is seen as the US capital of polyamory and ethical non-monogamy, the practice of openly and transparently having multiple relationships that go further than just sex.

Louis embeds himself with families who have made the bold decision to open up their relationships in a number of different ways, whether inviting others into existing relationships or allowing partners to seek romance elsewhere. He discovers that for many, more partners means more love and more happiness. But for others, multiple relationships have led to jealousy, upset and broken hearts.

Documenting the objectives of a neo-Nazi group that has actively recruited inside the United States military, gaining strength since the 2017 rally in Charlottesville, Va.

Dan Snow investigates a century of war trauma from WW1 shell shock to modern PTSD.

Historian Dan Snow breaks the silence around the devastating impact of war on the mental health of our soldiers. For 100 years, men and women who risked their lives for their country have continued to suffer on their return. In this film for BBC Two, Dan explores the challenge presented by an ongoing mental health crisis among war veterans. Dan discovers how the shell shock of WW1 has evolved into the cases of PTSD that modern soldiers suffer with today. Shockingly, lessons learnt from previous conflicts were soon forgotten. Battle trauma leads to alcoholism, broken families, violence and suicide on a shocking scale in the UK. He asks military psychiatrists and experts why we're still struggling to help the psychiatric casualties of war.

Dan shares frank and moving conversations with veterans of World War Two, the Falklands and Afghanistan, and also with relatives of those who fought in World War One. Jimmy Smith was traumatised after fighting in many of the major battles of the Great War. He was sentenced to death by court martial at only 26 years old for misbehaviour and desertion. A few decades later, Victor Gregg's marriage collapsed after witnessing the horrific violence of WWII bombing raids as a prisoner of war in Dresden. With each subsequent war, the symptoms changed, but the story remained the same. Ex-paratrooper Dave Brown has struggled with adjusting to civilian life since his service in the Falklands. Sean Jones survived an IED attack in Afghanistan in 2008. He was sent back for a second tour, without realising that he had been diagnosed with suspected PTSD.

Dan has many close family ties to the military campaigns of the First World War. Delving into previously unseen archives he reveals the difficult history of how Britain has reacted to the psychological consequences of warfare.

A powerful documentary following a group of citizens in West Virginia who take on a corporation after they discover it has been dumping a toxic chemical into the water supply.