The first time they flipped the switch on the ethereal spectacle known as the Tribute in Light, ground zero was still a disaster zone. Six months had passed since the World Trade Center fell. New Yorkers still felt sick and dazed, and they had grown weary of funerals.
When the time came, there was little pomp. The opera singer Jessye Norman sang "America the Beautiful." A few politicians made some brief remarks.
"And then the lights came on," recalled Michael Ahern, the theatrical producer who, for a decade now, has been orchestrating the tribute.
"I thought it was absolutely beautiful," he said. "And it seemed to mean a lot to people. People who were there _ the construction workers, the recovery workers _ told me they were immediately moved by it."
Few who saw it disagreed.
Of all the things that have been done in the past 10 years to memorialize the 9/11 dead, perhaps nothing has been as inspiring as the light tribute, which uses powerful searchlights to create a pair of otherworldly, sky-piercing blue columns in roughly the spot where the twin towers once stood.
Workers on Friday began setting up the array of 88 lights that make up the twin columns, rolling them into place atop a parking garage a few blocks from the trade center plaza.
Preparations for the display will go on for another week before the columns are switched on this Sept. 11, with a crew of around 30 technicians, electricians and stagehands doing most of the work. Every year, the Italian company that makes the lights, Real Space Cannon, sends a contingent to help get the spotlights in working order.
The trickiest part, Ahern said, is getting the light from each 7,000-watt bulb aimed straight at the sky. Each beam must be focused and leveled by hand, one at a time. If any one of them is off by a fraction of a degree, the effect is ruined. Since the towering beams can't be seen well from up close, spotters call in adjustments from viewing spots in Brooklyn, Staten Island, New Jersey and uptown Manhattan during a testing stage that lasts several days.
"It's more difficult than you imagine," Ahern said.
The lights are powered by a pair of generators, hauled to the site in tractor trailers. This year, each will run on biodiesel fuel.
At full power, the lights can be seen for many miles, depending on the weather. The columns themselves are created by the light that reflects off tiny dust and moisture particles in the air, so the look of the beams can change from night to night, depending on wind, fog and clouds. Ahern said people have reported sightings as far away as West Point, about 50 miles away.
Despite its popularity, the tribute's future is uncertain.
Its sponsor, the Municipal Art Society of New York, spends about $500,000 each year putting on the spectacle. Much of that money has come from donations and grants, but funding is only guaranteed through this year.
Even after a decade, the tribute also still does not have a permanent home. Originally, the beams were located on a lot in Battery Park City where the headquarters of Goldman Sachs now stands. Later, it moved to the garage, which is owned by the Metropolitan Transportation Authority.
There has been talk over the years of making space somewhere at the World Trade Center itself for the light installation, but a firm plan has yet to materialize.
Ahern said he is hopeful the city and the Municipal Art Society will find a way to let the tributes continue. This year, the society is soliciting donations from the public in an attempt to build an endowment. People can give $10 by texting the word "tribute" to the number 20222.
"I'm optimistic," Ahern said. "There are a lot of people who want it to happen."