President Trump's formal pledge to withdraw from the most ambitious climate accord to date - the Paris Agreement - comes at a time when we can see environmental emergencies right in front of our face. In California, raging fires burned nearly 100,000 acres, forcing thousands to flee their homes. Christiane speaks with the state's Lieutenant Governor to explore the crisis.

Five weeks from now, the British people face another general election, which once again attempts to resolve the bedeviling issue of how - or even if - the country should leave the European Union. George Osborne was in charge of the U.K.'s finances as Chancellor of the Exchequer when Britain narrowly voted for Brexit, and now is the editor of the Evening Standard. He joins the program from London.

Twitter co-founder Ev Williams stepped away from the company to turn his attention to Medium, an online publishing platform designed to showcase longer, more nuanced content. Williams tells Walter that while Twitter needs to take responsibility for the quality of its content, it shouldn’t risk losing its role as a place for the exchange of important ideas.

Legendary actress Julie Andrews became a household name with Mary Poppins, and has rarely left our screens since. Her new memoir, “Home Work,” covers her incredible years at the heart of Hollywood, including “The Sound of Music” and her sometimes difficult marriage to film director Blake Edwards. She joins Christiane in London to discuss mental health and her dazzling career.

Deadly protests have erupted in Iraq in the biggest wave of demonstrations since the fall of Saddam Hussein, echoing recent demonstrations in Lebanon. Two regional experts join Christiane to clarify the situation: Vali Nasr has served the State Department and spent years studying the region, while Karl Sharro is a Lebanese-Iraqi satirist who tweets razor-sharp commentary on the Middle East.

In corporate America, it is now widely accepted that diversity of gender, race, and background makes any organization perform better. It's the reason why StubHub President Sukhinder Singh Cassidy founded theBoardlist, a talent recruitment forum. She sits down with Hari to discuss how diversity can be bolstered in the tech industry.

Religion scholar Karen Armstrong is a former Catholic nun who rose to prominence after 9/11, when she was able to do what few others would, or could: explain Islam to an angry and terrified West. She joins the program to talk about her new book and her amazing life story, from religious nun to secular scripture expert.

How could a man as demonstrably evil as Adolf Hitler come to power? And what lessons can we learn from this today? As populations around the world once again turn to authoritarian leaders, the questions aren’t academic. Historian Brendan Simms' new book explores Hitler’s rise to power, and he joins the program to explain how it’s not just the times that give rise to the worst type of leader.

Ocean Vuong's debut novel, “On Earth We’re Briefly Gorgeous,” spent six weeks on the New York Times bestseller list. Semi-autobiographical, it is written in the form of a letter from a young Vietnamese-American to his illiterate mother. Vuong speaks with Michel about the force behind his creative spirit.

Harriet Tubman is a true American hero, and now her remarkable story is coming back to life in the new movie "Harriet." Tubman escaped slavery and came to be known as the Moses of her people for leading others to freedom on the Underground Railroad. Cynthia Erivo stars as Harriet Tubman, and Leslie Odom, Jr. plays a prominent abolitionist who connected Tubman to the network.

It's a somber day in American presidential history, as the House of Representatives votes to formally bring an impeachment inquiry into President Trump. Norman Ornstein understands the inner workings of Congress better than most, and joins the program to assess these historic developments.

Fires are raging in California, wreaking havoc from north of San Francisco down to Los Angeles. Hundreds of thousands of people are displaced and many more are simply in the dark, without power. Public policy expert and former Labor Secretary Robert Reich joins Christiane to assess the crisis.

With a readership of more than one and a half million, The Economist is at the forefront of the global conversation. Zanny Minton Beddoes became the magazine’s first female editor in 2015, and is consistently included in Forbes’ top 100 most influential women. She sits down with Walter to discuss her work, Elizabeth Warren, China, and what the Brexit vote really represents.

Antonio Banderas returns to his roots in “Pain and Glory,” a new film directed by – and based on the life of – legendary Spanish filmmaker Pedro Almodóvar. His role is a study on health, ageing and feelings, and is made all the more poignant considering Banderas himself only recently recovered from a heart attack. He joins the program to discuss a role that critics have called his most important.

After weeks of fact-finding behind closed doors, the House is gearing up to vote on the best way to present its impeachment inquiry to the public. Former Secretary of Defense William Cohen has been closely watching these hearings – as a member of the judiciary committee during Watergate, he was one of a handful of Republicans who voted for Nixon’s impeachment. He gives Christiane his perspective.

Award-winning actor John Lithgow is a familiar face on TV, film and stage. He’ll soon be seen portraying former Fox News chairman Roger Ailes in the film “Bombshell.” Before that, he has turned his hand to writing, with a new satirical poetry collection poking fun at the president. He discusses poetical satire with Hari.

In Beirut today, Lebanese Prime Minister Saad Hariri announced his resignation after two weeks of protests triggered by a proposed tax on WhatsApp calls. Mona Fawaz is a professor at the American University of Beirut and has been intimately involved in organizing the protests; she joins the program from Beirut, where demonstrations can still be heard.

Street protests worldwide have now reached Latin America: in Chile, President Sebastián Piñera has replaced his cabinet after days of violent protest and a misguided military crackdown. Meanwhile, Peru, Bolivia, Argentina and Colombia have also seen huge crowds on the streets. Juan Manuel Santos, former president of Colombia and a Nobel Peace Laureate, speaks to Christiane about this unrest.

Former Secretary of Veterans Affairs David Shulkin is the first former Trump cabinet member to speak completely openly about his experiences. He joins the program to reflect on the greater implications of Alexander Vindman's testimony to House investigators and reveal the inside story of the Trump administration.

At age 16, Aarti Shahani was visiting her father in the infamous Rikers Island prison, where he was serving time for a crime she says he was unwittingly involved in. In her new memoir, Shahani comes to terms with the 14 year long legal battle her family faced, and the resentment she felt at being brought to America as a child. She speaks to Michel about how all this shaped her American Dream.