Osama Bin Laden was killed by U.S. forces in a firefight yesterday, according to U.S. officials, who reported this news late last night and early this morning. Word of the death is rippling around the world, and crowds started gathering immediately in Times Square and at Ground Zero here in New York. Celeste Headlee reports live from Ground Zero.

Former spokesperson for the State Department PJ Crowley has an intimate knowledge of the U.S. government's mission to find Osama Bin Laden and bring him to justice over the last decade. Crowley joins us now, and reacts to the breaking news announced last night that the U.S. military did indeed kill and capture the 9/11 mastermind's body. George McAvoy, a New York resident whose brother died on 9/11 also speaks with us.

Following the news of Osama Bin Laden's death, Celeste Headlee is reporting live from Ground Zero this morning, where family of 9/11 victims and others have gathered to celebrate. Jared Ring, a New York City paramedic supervisor who left Eastern Long Island at 1:30 am to come to Ground Zero, speaks with us. Also, Miranda Nichols, a student from St. Johns University.

How did U.S. forces coordinate Osama Bin Laden's death? Takeaway Washington correspondent Todd Zwillich explains the nuts and bolts of how this happened, and reports on the reactions in Washington, D.C.

President Obama gave a statement last night, with little advance warning, on the dramatic U.S. attack on Osama Bin Laden. His statement confirmed rumors that had been swirling around Twitter and elsewhere for hours beforehand. 

How will the world react to the death of Bin Laden? Or perhaps more significantly, how will the world of terrorism react? We speak with Lydia Khalil, former counterterrorism analyst with the NYPD, as well as Christine Fair, assistant professor at the Center for Peace and Security, to learn more. 

As the world reacts to news that U.S. forces have killed Osama Bin Laden, details are emerging on how his death occurred. 

Veterans and families of victims of the 9/11 attacks are gathering at Ground Zero and elsewhere this morning, to celebrate and reflect on the news that Osama Bin Laden is dead. We speak with Dennis McKeon, a parishioner of St. Clare's Roman Catholic Church in Staten Island, which lost 29 members of its congregation in the 9/11 attacks. McKeon started the organization Where to Turn, which helps those affected by the attack. We also talk with Russell Galeti, first lieutenant in the Ohio National Guard.

BBC correspondent Quentin Somerville speaks with us from Kabul, Afghanistan, where President Hamid Karzai may not have had any warning before Osama Bin Laden's death.

Osama bin Laden has long been the most hunted man in the world. As the leader of Al Qaeda and the mastermind of the worst terrorist attack on American soil, he's served as the main target for the US war on terror. With his death, how will the terrorist organization change? We talk with Gideon Rose, author of How Wars End and editor of Foreign Affairs. 

Ailsa Chang, reporter for our flagship station WNYC, talks to us about what the scene is like in Times Square this morning, following the news that U.S. forces have killed Osama Bin Laden. 

The day after Sept. 11, 2001, journalists from around the world flocked to the Middle East to cover what would be become the defining story of the decade. Osama bin Laden instantly became a household name and Al Qaeda was America's new enemy. Now, nearly ten years later, the U.S. has achieved its original mission in Afghanistan — to find and kill bin Laden. To mark this historic moment, we talk with two veteran reporters who've been covering the story from day one: David Sanger and Rod Nordland, reporters with our partner The New York Times.

The military carried out the attack on Osama Bin Laden, which resulted in his death late last night. Former Assistant Secretary of Defense and defense analyst at the Center for American Progess Larry Korb speaks with us about how the military carried out this operation. 

How has Al Qaeda changed in the past few years, and what does this blow mean to the organization? Ahmed Rashid, journalist and author of Taliban: Militant Islam, Oil and Fundamentalism in Central Asia and other books, speaks with us about the future of Al Qaeda.

For years, the CIA hunted Bin Laden in Afghanistan and Pakistan. Michael Hurley, senior counsel to the 9/11 Commission and a former CIA officer who served in Afghanistan after 9/11, helped lead the search. He speaks with us about the significance of Osama Bin Laden's death. 

Edward Girardet, journalist and author of Killing the Cranes: A Reporter's Journey Through Three Decades of War in Afghanistan, is one of the few Western journalists to have met Osama Bin Laden in person. He speaks with us from the BBC's studio in Delhi, India, about the news of Bin Laden's death.

There are, of course, major political ramifications of Osama Bin Laden's death for President Obama today. He can now take credit for the killing of Bin Laden. David Remnick, editor of The New Yorker and author of The Bridge: The Life and Rise of Barack Obama, speaks with us about what Bin Laden's death will mean for Obama. 

The economic markets have responded positively to the death of Osama Bin Laden. Louise Story, Wall Street and finance reporter for our partner, The New York Times, talks with us about what's happening on Wall Street and why markets responded so positively. 

This morning's news of Osama Bin Laden's death has set up reactions across the world. We've gathered some notable reactions from the international press, including The Times of India, The UK Guardian, and Le Monde. A Times of India editorial says: "The finger of suspicion is now pointing squarely at the Pakistani military and intelligence for sheltering and protecting Osama bin Laden before US forces hunted him down."

Mark Mazzetti, national security correspondent for The New York Times, speaks to us about news that Osama Bin Laden's trusted courier was integral to the operation that led to his killing. 

Secretary of State Hillary Clinton speaks about Osama Bin Laden's death, saying that "justice has been served," but that the battle against Al Qaeda has not ended with Bin Laden's death.

This morning, reports have surfaced linking Bin Laden's death to intelligence gathered at the notorious Guantanamo Bay holding facility in Cuba. If keeping prisoners detained has resulted in the death of America's most-wanted tourist, what does that mean for how we'll treat prisoners in the future? We speak about this with Richard Perle, Assistant Secretary of Defense under President Ronald Reagan.