About 3,000 drones have lit up the skies of New York during rehearsals for the 25th anniversary of the September 11 attacks. The drones created various light patterns in a coordinated display that will be part of the tributes to the victims of the 2001 attacks. Footage from the rehearsals shows the city's sky filled with thousands of points of light moving in sync.
The September 11, 2001 attacks killed nearly 3,000 people and remain one of the most tragic events in modern U.S. history. The drone display is expected to be a highlight of this year's commemorations.
