From the 1880s up until World War II, New York City's North Brother Island island served as a quarantine location for patients with infectious diseases, including the infamous Typhoid Mary.

North Brother Island sits next to Rikers Island prison complex and was abandoned in 1963 after a failed stint as a drug rehabilitation center.

It's illegal to visit North Brother Island without permission from the city due to hazardous ruins and its status as a bird sanctuary.

In 2017, Business Insider visited the island, learned about its sordid history, and photographed the dilapidated state of its buildings.

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Less than a mile from Manhattan exists a little-known island that has been abandoned for over half a century and whose history is checkered with death, disease, and decay.

"North Brother Island is among New York City's most extraordinary and least known heritage and natural places," wrote the authors of a 2017 University of Pennsylvania study about the location.

The city owns the 22-acre plot of land in the East River, which sits between the South Bronx's industrial coast and a notorious prison: Rikers Island.

Almost no one is permitted on North Brother Island and its smaller companion, South Brother Island, except for birds. But even they don't seem to want to live among its crumbling, abandoned structures.

In 2017, producers for the Science Channel obtained the city's permission to visit North Brother Island — and the crew invited Business Insider to join.

Here's what we saw and learned while romping around one of New York's spookiest and most forgotten places.