THE great-great-great-grand-daughter of a Huddersfield industrial magnate travelled from her home in America to tour his former factory.
Priestroyd Mills, in Firth Street, built by John Haigh in 1835, is being converted into hundreds of flats.
Elizabeth Gordon, from Michigan, saw for herself the inside of the building, used first as a factory making carding machinery for the woollen industry, then as an ironworks.
One day she hopes to write a book about her family.
"I want to walk where my ancestors walked," she said. "I want to be inside the building and I want to touch what they touched.
"That's why this is so exciting for me," she added as she walked higher and higher through the building.
"It's great to be able to look out of windows and see the mills in the background and the Yorkshire landscape.
"It brings the history alive," she said as she explored the five-storey building, taking photos.
Mrs Gordon, a mother-of-one who is a psychologist, travels to Yorkshire every two years to delve into her family background.
"I'm really interested in the details and the history of generations way back," she said.
At one point, it was feared that Priestroyd Mills would be demolished. But Kirklees Council asked the Government to list the building and it was saved.
Mrs Gordon wrote a letter urging that the ironworks be preserved.
Through elderly relatives, papers bequeathed to her and repeated trips to the archive section at Huddersfield Library, she is slowly building a vivid picture of John Haigh.
Mrs Gordon said: "John Haigh was a self-made man. He was actually apprenticed as a child. I think he was nine."
She said the family appeared humble about their achievements and vast wealth.
"I would say they were modest people. I haven't found they in any way lived the high life," added Mrs Gordon.
She was given a tour of the Firth Street building by Richard Brook, sales and marketing manager of Lanson Developments, who are converting the building into flats.
He organised the day and presented Mrs Gordon with a photo of the inside of Priestroyd Mills as a memento.