They came to Lower Manhattan from around the world to visit the 9/11 Memorial on an unseasonably warm winter day. They came to see where it had happened — where terrorists had crashed two jetliners into the World Trade Center towers, destroying them in horrific plumes of ash, flames and pulverized concrete. More.

The final passing of the James Zadroga 9/11 Health and Compensation Act was a major milestone for first responders. Zadroga was a New York City detective whose heroic response to the terrorist attacks the morning of Sept. 11 became the direct reason for his death. More.

It’s been more than 15 years since the 9/11 attacks spread a cloud of toxic chemicals and dust across Lower Manhattan, and advocates say that many of the people who were harmed by it still don’t realize how they were affected - or that help is available. More.

Chronic health conditions ranging from cancer to “World Trade Center cough” have been attributed to exposure to dust from the September 11, 2001, attack and collapse of the World Trade Center towers. Biology Professor Ann Marie DiLorenzo and her research team have been determining the impact of that dust on lung cells since 2007. More.

Sometime Tuesday, two days after leaving her East Brainerd home, Marvina Baksh will walk into a courtroom at the U.S. military prison at Guantanamo, Cuba, and come face-to-face with the men the U.S. government says killed her brother. But she says she will have no hatred for them, more than 15 years after the Sept. 11 attacks that killed nearly 3,000 people and shattered her tight-knit family. More.

The White House said Tuesday that the Guantánamo Bay detention center in Cuba will still be open when President Barack Obama leaves office, conceding that a core campaign promise will go unfulfilled. Administration officials had long insisted that the president was continuing to work toward closing the facility even when it became obvious that it would no longer be possible for practical reasons before President-elect Donald Trump takes office Friday. More.

The recent conclusion of Dylann Roof's trial is the latest reminder that homegrown terrorism has become part of the fabric of life in America. This problem shows no signs of fading, yet reveals a threat that is both rarer and more complex than simple explanations suggest. More.

The National September 11 Memorial & Museum at the World Trade Center has finally been able to add five missing portraits of people who died on Sept. 11, 2001. This was largely thanks to what Jan Ramirez, senior vice president of collections and chief curator at the Memorial and Museum, calls "a small, wonderful miracle." More.