For the past 12 years Tribecan Todd Stone has been painting the progress of the World Trade Center from above, perched in a series of makeshift studios in unfinished spaces across the site’s towers. He’s watched the memorial pools emerge, the towers unfurl and a new city emerge from rubble.

But his intimate connection to the site, like so many of us, starts with the events of 9/11, as he watched the towers collapse from his apartment window on Thomas Street. His first instinct was to rush to the site and help, but his wife told him to stay.

“I was on my roof when the first tower fell. It was clear to me the extent of the disaster. My wife was with me. I said, we have to go down there, and she said to me that my job was to watch. That I’m an artist. And I spent the entire day drawing and painting on my roof, opening myself up to the horrors of the day.”

And he didn’t stop. In the weeks and months that followed, he continued to paint the site — to bring forth and witness, as he puts it, the events he saw from his rooftop and from the streets of the neighborhood.

Years later, he would send a couple of those paintings that included the construction of 7 World Trade Center to Silverstein Properties. In turn they invited him to become ​one of ​the trade center’s artist​s​ in residence, installing him in empty spaces in 7 WTC, 4 WTC and most recently, 3 WTC, where he paints from an unfinished, 360-degree space on the 71st floor — a 40,000-square-studio 800 feet up in the sky.

A retrospective of those 20 years of painting are on view now at the NYC Culture Club gallery space at the Oculus, through Sept. ​30.

The events of 9/11 completely shifted his career. Before that day he had a body of work of abstracts (he’s lived and painted in the city since 1975, and lived on Thomas Street for 40 years) and he had been painting the skyline from Tribeca for a decade at that point, often the view a seen through his studio window. But once the towers came down, his focus narrowed to our streets and our city in those 12 blocks from Thomas to Liberty.

“My artwork is based on the six blocks between Thomas Street and Liberty Street,” Stone says. “It’s been about the distance between Tribeca and that emptied sky. And about being in that emptied sky looking down on Tribeca.”

When he first set up his easel on the 48th floor of 7 World Trade in 2009, there was an empty pit below him. From that day he committed his paintings to the community of people that brought the site back to life over 20 years. He calls it a celebration of their work. “I’m focused on the renewal of Lower Manhattan,” he says. “It’s spectacular what’s happened down here. It’s a new city. And my work is a narrative of that rebuilding effort.” He has also painted the views — looking out over the entire city and harbor, in daylight and at night, for miles to the horizon.

But his original series from 2001, which he titled “Witness,” is what is most sacred to him, and those images he still finds hard to absorb, revisit and accept, even though it was his hand and his brushes that created them. There are hundreds of images of the events of 9/11 — some are seared into our minds — but few were emotionally processed over time by someone who witnessed the towers’ fall firsthand.

“These paintings are not momentary captures of something that happened — they are different that way than photographs,” Stone says. “They are elegies to the people who died, grounded in the dust that settled in my studio as I chose to stay here with my family as the fires burned. All of our lives were completely transformed that day. This was what I could do — I had to make art out of that horrible thing that I witnessed.”