The challenge when writing History is to break the glass that separates us from the past. To connect somehow with those who lived before us and turn them back into people — not flat abstractions in funny clothes.

The glass-breaking moment for me, when I set out long ago to write a history of the Triangle Shirtwaist factory Fire — the 1911 industrial disaster that shaped the politics of New York and later the entire nation — came when I learned that some of the victims, moments from death yet cheerfully unawares, were singing at the end of their workday. “Every Little Movement,” a hit Broadway show tune, was their equivalent of the latest from Taylor Swift. Some joke or passing remark or reference to a boyfriend had reminded one of them of the lyrics, and when she launched in, others joined her, as happy humans often do.

They were flesh and blood, as real as you and I. And then they were gone — incinerated in their ninth-floor death trap or smashed on the Greenwich Village pavement where they plunged. No publication even bothered to record all their names.

Now, New Yorkers and visitors to the city will be able to have their own glass-breaking moments at the site of the historic fire, which was the deadliest workplace disaster in city history until the day known as 9/11. The Triangle Fire Memorial, a project years in the making, will be dedicated on Wednesday at the corner of Washington Place and Greene Street near Washington Square in the heart of Manhattan.

The 146 fire victims — most of them immigrant women from Italy and Eastern Europe — will be restored as actual names of actual people, at the very spot where they passed into history. Their names are cut into the flowing steel of the monument, which — when all the pieces are installed this winter — will stretch like ribbon to ninth-floor windows, then tumble back toward street level, where it will spread its arms to embrace the building where history happened. Light shining through the incised names will reflect on a polished surface, where they will appear as if glowing.

Americans learned to build high-rise buildings before they figured out entirely the dangers that height posed. Thus, an energetic young researcher named Frances Perkins had just begun a job looking into fire risks in factory lofts when she visited a friend for tea on March 25, 1911. Her visit was interrupted by the clanging of fire bells. Looking outside, she saw smoke rising from a nearby 10-story tower.

It was about 4:45 p.m. on a warm, bright Saturday. As the workday ended at the city’s busiest blouse factory, an ash or ember — probably from a cigarette — fell into a bin of cotton scraps, which exploded into flames. Quickly consuming the eighth floor, the fire spread rapidly to the ninth, where it trapped scores of workers.

Along with thousands of New Yorkers weary of winter and enjoying the day, Perkins came running to the scene just as dozens of trapped workers leaped and fell from the windows above.

For the shocked city, the question of fire danger was settled. New Yorkers also knew that the same factory that burned had also been the center of a great labor uprising of female workers. The energy of a young century — labor energy, feminist energy, progressive energy — poured into the frame of this catastrophe. Perkins switched gears to study the question of what to do about unsafe workplaces, and from there she studied the needs of American workers more generally. In 1933, she became the first woman to serve in a president’s Cabinet, as secretary of labor to Franklin D. Roosevelt.

The Triangle fire, she said, was “the day the New Deal was born.”. . .

History becomes irresistible when sympathy connects us with the past. People lost behind glass come back to life in our minds and hearts, pull us into their stories.

We see ourselves in them. We draw strength from wraiths. We learn courage from ghosts.