In 2002, six months after September 11th, a group of artists and designers conceived of an installation that would honor the lives lost on 9/11 with a tribute that evoked the image of the destroyed towers. Tribute in Light first debuted on March 11 and ran through April 14 in a vacant lot across from ground zero on West Street.

The installation was conceived by several artists and designers who were then brought together under the auspices of the Municipal Art Society and Creative Time: John Bennett, Gustavo Boneverdi, Richard Nash Gould, Julian LaVerdiere and Paul Myoda, with lighting consultant Paul Marantz, and it continued for a decade that way, though over the years the project was threatened to end. Then in 2012, the National September 11 Memorial & Museum transitioned operation of the tribute from the Municipal Art Society to the memorial foundation.

Now the tribute is assembled on the roof of the Battery Parking Garage south of the memorial, at 80 Greenwich, supported by Con Edison and produced by Michael Ahern Production Services — and it is not twin beams at all. I toured it for the first time, on the roof for the test of the lights on Sept. 5, and watched as teams of technicians manually switched on two sets of 44 7,000-watt xenon lightbulbs arranged into 48-foot squares echoing the shape of the former Twin Towers. (It must cost hundreds of thousands to produce, but they would not divulge the budget.)

The beams reach four miles into the sky and can be seen for 60 miles. (And the producers now work with the NYC Bird Alliance and the Audubon Society to watch for bird migration; when the birds begin to gather, the lights are turned off for a short time.)

Power is brought in for the event, with generators set up on West and cables run from there to the seventh floor. The team spends several days moving the lights to get the perfect shape, and making adjustments for weather conditions. For the rest of the year, the lights are stored elsewhere in the garage.

On Sept. 5, the first light flicked on at 8:05, and as each one was added, the scene was more moving and more spectacular. The mist that night moved through the beams — it added motion to the static light. Technicians moved through the maze of lights, brushing the top surface and checking each one. As the memorial’s Josh Cherwin said, it brings the towers back to life.

And then, a half hour later, the lights were extinguished, one by one.