See Mary Ellen Mark’s Most Memorable Photo Essay

Mary Ellen Mark frequently photographed people on the fringes of society. By training her camera on those who went unseen, she willed them to be just the opposite.

In 1983, a collection of these photographs was published in a LIFE Magazine photo essay called “Streets of the Lost.” The unseen in this case were the homeless youth of Seattle. When Mark’s indelible images hit newsstands, a once-invisible population was brought to life by an unforgettable collection of very real human faces.

Mark, who died Monday at 75, chose Seattle for this project because it was known as one of America’s most livable cities. She wanted to show that if kids were living on the street there, then they were living on the streets of every major American city. She didn’t photograph from a distance, but rather implanted herself in the daily lives of her subjects, and this intimacy allowed her to capture portraits of them at their most vulnerable.

Mark photographed children holding guns, eating out of dumpsters and injecting their arms with needles. To provide context for the stories she told visually, journalist Cheryl McCall explained the situations that led them to resort to prostitution, theft and violence. They were running from abuse, from alcoholic parents and families who couldn’t—or wouldn’t—care for them. Though their reasons varied, they were all running from something.

The impact of “Streets of the Lost” was so great that Mark’s husband, Martin Bell, convinced Mark and McCall to join him in making a documentary film following up on the lives of several of Mark’s subjects. The result, Streetwise, was nominated for an Academy Award.

Mark and Bell continued to return to Seattle to photograph the young men and women they met there. As Mark told TIME this past March, speaking about another memorable portrait of a child, “Going back is something that’s always fascinating to me.” In 2013, she and Bell raised more than $85,000 on Kickstarter to develop a follow-up documentary focusing on the life of Erin “Tiny” Blackwell, who featured prominently in the original photos and film. Their final collaboration, titled Streetwise: Tiny Revisited, has yet to be released.

Mark’s portraits of these young people—Tiny and Rat, Laurie and Patti and Mike—are arresting without resorting to sensationalism. As Mark told TIME, “I don’t like to photograph children as children. I like to see them as adults, as who they really are. I’m always looking for the side of who they might become.”