A little-known island just offshore from the Bronx in New York City serves a massive cemetery, where around 800,000 bodies have been buried over the past 150 years.

Those laid to rest at Hart Island typically are the poor, those without next of kin or the unknown.

But thousands are still buried in mass graves there every year, and some have been buried there as a result of bungled paperwork.

Only those who can prove they have relatives buried there are allowed to visit the cemetery, and a foundation founded by an artist is helping families locate loved ones on Hart Island.

Al Jazeera's Scott Heidler reports from New York City.