Almost a million images of New York and its municipal operations have been made public for the first time on the internet.
The city's Department of Records officially announced the debut of the photo database.
Culled from the Municipal Archives collection of more than 2.2 million images going back to the mid-1800s, the 870,000 photographs feature all manner of city oversight - from stately ports and bridges to grisly gangland killings.
The project was four years in the making, part of the department's mission to make city records accessible to everyone, said assistant commissioner Kenneth Cobb. "We all knew that we had fantastic photograph collections that no one would even guess that we had," he said.
Taken mostly by anonymous municipal workers, some of the images have appeared in publications but most were accessible only by visiting the archive offices in lower Manhattan over the past few years.
Researchers, history buffs, filmmakers, genealogists and preservationists in particular will find the digitised collection helpful. But anyone can search the images, share them through social media or purchase them as prints.
The gallery includes images from the largest collection of criminal justice evidence in the English-speaking world, a repository that holds glass-plate photographs taken by the New York City Police Department.
It also features more than 800,000 colour photographs taken with 35mm cameras of every city building in the mid-1980s to update the municipal records, and includes more than 1,300 rarely seen images taken by local photographers of the Depression-era Works Progress Administration.
Among the known contributors to the collection was Eugene de Salignac, the official photographer for the Department of Bridges/Plant & Structures from 1906 to 1934. A Salignac photograph, taken on October 7, 1914, and now online, shows more than a half-dozen painters lounging on wires on the Brooklyn Bridge.
"A lot of other photographers who worked for the city were pretty talented but did not produce such a large body of work or a distinct body of work," said Michael Lorenzini, curator of photography at the Municipal Archives and author of "New York Rises" that showcases Salignac images.