Instagram says it's looking to discourage users from focusing on their physical appearance in the wake of a major Wall Street Journal investigation, which revealed that researchers repeatedly found the app was toxic for teenage girls in particular, yet publicly downplayed its mental health implications. Georgia Wells reported the story for the WSJ and is joined by tech ethicist Tristan Harris.

Extreme weather events have laid bare the threats posed by the climate crisis, yet while activists rally to save the planet, many of them face increasing violence. 227 environmental activists were murdered last year, according to Global Witness, which says most of the killings happened in Latin America. Global Witness CEO Mike Davis and activist Margarita Campuzano join the program to discuss.

Gavin Newsom beat a recall challenge last night, in part by emphasizing his commitment to mask and vaccine mandates. It’s a stark contrast to Republican governors in states like Texas and Florida. Former GOP strategist and Lincoln Project co-founder Steve Schmidt says their anti-science stance is a selfish ploy to woo the far right. Schmidt joins Michel Martin to discuss the current climate.

Many wealthy nations are preparing to start rolling out booster shots. In the UK, the most vulnerable will be offered a third dose from next week, while in the U.S., the Biden administration is pushing to make them widely available by Monday. Yet in poorer countries, many are still waiting for their first shot. Dr. Hans Kluge joins Christiane to discuss vaccine inequity.

Colin Kaepernick helped ignite a movement when he took a knee during the national anthem, a silent protest against police brutality and racial inequality in America. Sports writer Dave Zirin examines the lasting impact of this moment in his new book, "The Kaepernick Effect," as he explains to Hari Sreenivasan.

Boxing legend Muhammad Ali risked jail, being stripped of his titles and financial ruin, all to defend his faith and Black rights. Now his legend has drawn the eye of award-winning historian and filmmaker Ken Burns, whose new documentary traces the arc of Ali’s life and the history he lived.

Tennis can be a hard and solitary sport, so it’s no wonder that center court has become a beacon for vital conversations around mental health. Seven-time Grand Slam Champion John McEnroe knows all about the pressures of the game. He joins Christiane to react to this year's tournament and reflect on his career.

The U.S. is racking up 1,500 COVID-19 deaths each day, almost entirely among the unvaccinated. Anti-vaxxers are finding success by zeroing in on the word “freedom,” a usage explored in a recent New York Times piece by science journalist Tara Haelle. She joins the show alongside infectious disease specialist Dr. Jeanne Marrazzo.

North Korea is claiming a successful test-firing of new cruise missiles, bringing renewed focus to the Korean peninsula. It’s a region Matt Pottinger knows well, having reported extensively from Asia as a journalist before he became deputy national security advisor to President Trump. Pottinger speaks with Walter Isaacson about the threat to the region and why he resigned from the White House.

68-year-old Kenneth Chamberlain was at his home in White Plains, New York, when he accidentally triggered his medical alert device, prompting a visit from the police. What should have been a simple check-in ended with Chamberlain's death. A new film takes viewers through his final hours. Morgan Freeman, the executive producer, joins the show alongside Kenneth Chamberlain, Jr. and Frankie Faison.

On the morning of 9/11, FDNY Assistant Chief Joe Pfeifer led his firefighters to investigate a possible gas leak reported in downtown Manhattan. He had no idea what was coming. Pfeifer documented his experience as the first fire chief to reach Ground Zero in his memoir, "Ordinary Heroes." He spoke to Hari Sreenivasan about the day everything changed.

Retired U.S. Army Colonel Lawrence Wilkerson, as chief of staff to the Secretary of State, helped prepare the now infamous 2003 speech at the U.N. Security Council in which Secretary Powell falsely claimed Saddam Hussein had weapons of mass destruction. The speech led the U.S. into Iraq and left Wilkerson with a lifetime of regrets. Wilkerson joins the program to discuss.

Twenty years on from the September 11th attacks, the Taliban are in power in Afghanistan. How did it turn out this way? And what, if anything, was accomplished by American intervention? Roya Rahmani, Afghanistan's first female ambassador to the United States, left her post in July. She joined Christiane from Washington.

Sandra Cisneros is best known for her acclaimed novel "The House on Mango Street." Her new novella, "Martita, I Remember You," tells a story of a struggling young writer in Paris, with many details closely resembling the author’s own life. She joins the show from Mexico.

The Taliban’s return to power coincides with the 20th anniversary of the 9/11 attacks. For many Americans, it was the first time they learned of the group and their role as hosts to Al-Qaeda in Afghanistan. A new series from National Geographic gives voice to the people who survived the attack on the World Trade Center, and its director joins the show to discuss his portrait of that day.

What can life be like for the women of the Afghan countryside, who have suffered through decades of civil war and foreign occupation? New Yorker contributor Anand Gopal embedded himself among the people in places rarely covered by Western media. The result is his in-depth article “The Other Afghan Women”. He joins the show to discuss.

In the aftermath of 9/11, President George W. Bush embarked upon what quickly became known as the war on terror. What did this actually entail -- and what are its consequences today? Spencer Ackerman, a longtime national security reporter, speaks with Hari Sreenivasan about his new book, "Reign of Terror."

Will Afghanistan become a terrorist safe haven? Few people are better placed to answer than Ali Soufan, a former FBI special agent who made his name investigating Al-Qaeda plots before 9/11. He speaks with Michel Martin about why the terrorist threat is far from over, and why he believes a more dangerous phase has begun.

With Afghanistan's food supplies, finances, and public services on the point of collapse, the U.S. and its allies now must decide on a course of action. Democratic Senator Chris Murphy sits on the Senate Foreign Relations Committee and has just concluded a congressional delegation to the region.

What is America’s appropriate role on the world stage? Kori Schake has held top jobs in the Defense and State Departments and worked as a foreign policy advisor to Senator McCain’s 2008 presidential campaign. She currently is director of foreign and defense policy at the conservative American Institute Policy.