She walked the city streets for hours, capturing the highs and lows of urban life with the all-seeing lens of her camera.
When the day drew to a close, Vivian Maier would return to her small attic room overflowing with undeveloped rolls of film, and resume her life as a nanny.
Maier spent much of her life caring for children of Chicago's wealthy families, but she was also one of 20th century's most talented street photographers. However, it was not until after her death that her work came to light, having been discovered by chance at an auction. Boxes filled with thousands of negatives were bought by John Maloof, a thrift-market enthusiast who was intrigued by the clarity and power of Maier's photos, and eventually posted them online -- to huge acclaim.
By Milena Veselinovic, for CNN Courtesy Vivan Maier/Maloof Collection
The images -- taken between the 1950s and 1990s -- went viral, and Maloof, who at first thought he had stumbled upon the opus of a seasoned photojournalist, started tracking down more of Maier's photographs. He later created the Maloof Collection, which encompasses 90% of Maier's work.
Since then, the reclusive nanny's images of grit and glamor of the urban landscape have been exhibited around the world, drawing comparisons to the great photographers of 20th century, such as like Robert Frank and Diane Arbus. Her mysterious life spurred Maloof to make a documentary, called Finding Vivian Maier, which is currently in cinemas. Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
"There are two sides to her allure," says Maloof. "The photos are really good, and it's almost like viewers are discovering a piece of history, which is exciting. The other part is that her story is really fascinating and mysterious, and people like a good mystery.
"They are intrigued by it and want to solve it." Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Large sections of Maier's life still remain a mystery. But what is known is that she was born in 1926 in New York City, to a French mother and an Austrian father. She spent much of her youth in France, before returning to the U.S. in her mid-twenties and finding work as a nanny. Throughout that time she compulsively documented street life, without shying away from down-and-out neighborhoods and difficult topics.
"Her choice of her subject matter was extraordinary," says Brett Rogers, director of London's Photographer's Gallery. "She went for people who lived in the margins of society, people other photographers didn't necessarily look at in that way -- children, old people, the poor. Maier was using her camera as a tool to explore her society from the 1950s up to 2009 when she died." Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Rogers also attributes the wave of interest in Maier's work to the revival of street photography, where photographers capture what they see with no staging or construction.
"People see it as very honest and reflective of the abilities of the photographer, and there is a great resurgence of this style right now," she said. Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Maier would sometimes bring her young charges along on her long exploratory walks, on one occasion taking a little girl to Chicago's stockyard where in the 1950s corpses of trampled sheep were a common sight.
"She exposed the children of wealthy families to the grit of urban life," said Maloof. "In that way they perhaps got a taste of how the world really is outside their sheltered, privileged communities." Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Part of Maier's great skill was in capturing the full breadth of urban life, effortlessly switching between images of deprivation and glamor. Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
There is an intimacy in Maier's photos, which may have been aided by her use of the Rolleiflex camera which is held at chest level, allowing her to look straight at the people she was photographing. "There is trust between Maier and her subjects, and the photos have great intensity -- perhaps because she was maintaining eye contact with them," said Rogers.
While she is primarily known for her black and white images, Maier also left a small, but equally impressive, body of work in color. Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Maier's perceptiveness was perhaps also shaped by the early years she spent in France, allowing her to observe details of American life with the particularly sharp eye of an outsider.
"Her sensibility was certainly very European," says Rogers. "At the time when she lived there, Europe was the center of the sort of humanistic photography she would go on to create." Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
A number of Maier's photographs feature some of the most celebrated personalities of her era, such as Audrey Hepburn, Frank Sinatra, and in this picture, Kirk Douglas.
"She was a film buff, she knew a lot about foreign films and where all the premieres were taking place," says John Maloof. "She would also go to book signings and take photos of the authors." Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Maier's thirst for culture took her on a round-the-world trip, and she visited Europe, the Middle East, Asia and the Caribbean. As with most things in her life, Maier undertook the journey alone, and staying true to her subject matter, her lens was again drawn to the downtrodden and dispossessed people she came across. Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
The quality of her prints was of great importance to Maier, and she would always send them to France to be developed. However, one of the great unanswered questions about her story is why, after taking over 150,000 images in her life time, she decided not to show them to anyone.
"She understood her works were quite special, but perhaps she didn't want people telling her what to do with them," says Rogers. "Although it does seem strange that she wouldn't have wanted to share her view and vision of the world with other people." Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery
Rogers adds that the profession of a nanny, a person always present but never the focus of attention, probably allowed Maier to take a step back and have an unfettered perspective of the world.
"She was a solitary individual but this made her a great observer. She never got married she was very proud that she was independent and remained so until her death. It was part of her identity," she said. Courtesy Vivan Maier/Maloof Collection/Howard Greenberg Gallery