Watch the trailer.

In remembrance of the attacks on September 11 in New York City, Washington DC, and Pennsylvania 20 years ago this year, experience the virtual premiere of “9/11: One Day in America,” a four-night limited series from National Geographic chronicling the events of that day through gripping first-person narratives of the first responders and survivors who were there.

To create this docuseries, which was produced in official collaboration with the 9/11 Memorial & Museum, the filmmaking team sifted through 951 hours of archival footage to make an immersive and emotionally charged seven-hour account of that fateful day 20 years ago. It offers a comprehensive and intimate look at how the tragic events of that day impacted so many lives, capturing the heroic acts of selflessness and bravery of strangers saving one another at all costs and revealing the triumph of the human spirit when tested beyond belief.

The virtual screening will be followed by a discussion with Emmy and Academy Award-winning producer T.J. Martin, series producer Caroline Marsden, and two of the series’ subjects in conversation with ABC News’ Linsey Davis.