Henderson Island, an uninhabited atoll in the South Pacific, is so isolated that it’s one of the few places in the world “whose ecology has been practically untouched by a human presence.”

That is, at least, according to its description by a United Nations group, which named Henderson Island a UNESCO World Heritage site in 1988.

“The inhospitable nature of the island, together with its remoteness and inaccessibility, has so far effectively ensured its conservation,” UNESCO stated. “As a near-pristine island ecosystem, it is of immense value for science.”

In reality, the remote island has become the final resting place for an estimated 38 million pieces of garbage, according to researchers who arrived on its shores in 2015 and were stunned to find the atoll’s once-undisturbed white-sand beaches littered with trash. Nearly all of it was made of plastic.

Researchers believe that about 3,500 pieces of trash are continuing to wash up there daily, and that Henderson Island now has the highest density of plastic waste in the world, according to a report published Tuesday in the scientific journal Proceedings of the National Academy of Sciences.

“The quantity of plastic there is truly alarming,” Jennifer Lavers, a co-author the report, told the Associated Press. “It’s both beautiful and terrifying.”

Images provided by Institute for Marine and Antarctic Studies at the University of Tasmania, where Lavers is a research scientist, show thousands of brightly colored items strewn upon Henderson Island’s sands: water bottles, pieces of netting, plastic helmets, garden containers and other debris so broken down that its original purpose is unrecognizable.

The dramatic accumulation is the result of human activity from thousands of miles away, the report states. Henderson Island is uninhabited and its closest neighbor, Pitcairn Island, lies about 70 miles to the west and is home to only about 40 people. The nearest major population center is more than 3,000 miles away.

However, Henderson Island also happens to be situated on the western edge of a circular system of ocean currents called the South Pacific Gyre, according to the report. Because of its location and the movement of those currents, the island naturally becomes a repository for floating debris from around the world – despite not being home to a single human.Researchers say garbage had been carried there from China, Japan, South America, Europe, the United States and Russia.