We love the iconic portraits of industrial workers found on the Made in America Forever® stamps—and while it’s obvious that those pictured are working hard, have you ever thought about the work of the photographer who created the images?

Documentary photographer Lewis Hine (who was born on this day in 1874) created 11 of the 12 stamp images, and four of those document the construction of the Empire State Building, the tallest building in the world from 1931 to 1972. Look at the photos, and take a second to think about this: Where exactly was Hine standing when he took those photos of construction workers balancing on steel girders, with nothing but empty sky behind them?

Capturing those classic scenes involved some risk. In 1930, Hine wrote about one of his most adventurous days at the Empire State Building in a letter to a friend:

My six months of skyscraping have culminated in a few extra thrills . . . just before the high derrick was taken down, they swung me out in a box from the hundreth floor—a sheer drop of nearly a quarter of a mile—to get some shots of the tower. The Boss argued that it had never been done and could never be done again and that, anyway, it’s safer than a ride on a Pullman or a walk in the city streets. So he prevailed.

During his career, Hine also achieved fame as a social reformer.

Best known for pictures of immigrants, child laborers, and industrial workers, he viewed his subjects with compassion and their harsh surroundings with an unflinching eye. His photographs of children working in mines, mills, and factories led Congress to try to regulate child labor, but the Supreme Court declared early laws unconstitutional.