Three years ago, the Sandy Hook tragedy unfolded in Newtown, Connecticut.
The event marked the unthinkable as a gunman killed 20 children and six staff members at Sandy Hook Elementary School, as well as his own mother, before turning the gun on himself.
President Obama wiped away tears as he spoke at a news conference after he learned the news.
He said: "They had their entire lives ahead of them, birthdays, graduations, weddings."
On the three-year anniversary of the tragedy, tributes poured in to the victims.
The 26 people who lost their lives at the school were: Charlotte Bacon, 6; Daniel Barden, 7; Rachel Davino, 29; Olivia Engel, 6; Josephine Gay, 7; Ana M. Marquez-Greene, 6; Dylan Hockley, 6; Dawn Hochsprung, 47; Madeleine F. Hsu, 6; Catherine V. Hubbard, 6; Chase Kowalski, 7; Jesse Lewis, 6; James Mattioli, 6; Grace McDonnell, 7; Anne Marie Murphy, 52; Emilie Parker, 6; Jack Pinto, 6; Noah Pozner, 6; Caroline Previdi, 6; Jessica Rekos, 6; Avielle Richman, 6; Lauren Rousseau, 3-; Mary Sherlach, 56; Victoria Soto, 27; Benjamin Wheeler, 6; Allison N. Wyatt, 6.
Notable names like Bernie Sanders and Martin O'Malley have taken to Twitter to remember the day.
Since #SandyHook Congress has done nothing to prevent this senseless violence from happening again. That is unacceptable. We must act now.— Bernie Sanders (@SenSanders) December 14, 2015
As a father, the tragedy at #SandyHook weighs deeply on my heart today. We must enact real gun safety laws & prevent future tragedies.— Martin O'Malley (@MartinOMalley) December 14, 2015
Others like Congresswoman Debbie Wasserman- Schultz have tweeted:
Remembering is not enough. Since #SandyHook, 90K Americans have died from gun violence. We need to act to keep guns out of the wrong hands.— D Wasserman Schultz (@DWStweets) December 14, 2015
Sandy Hook joined a long line of horrific school shootings, including 1999’s Columbine horror, in which 15 were killed, and the Virginia Tech shooting of 2007, where 33 people perished.