Lying just south of the equator, the eight square-mile pinprick of land is a far cry from the postcard image of a South Seas paradise.
Decades of phosphate mining have left much of the island of Nauru – the world's smallest republic – a parched moonscape.
While life is tough for its 11,000 inhabitants, it's arguably harder for a man who may qualify as the loneliest refugee in the world.
Mohammed Sagar was one of 1,500 refugees from the Middle East and Afghanistan who were sent to Nauru as part of Australia's "Pacific Solution," a policy under which Canberra outsourced the problem of asylum-seekers trying to reach its shores by sending them to poverty-stricken neighbors.
The refugees were intercepted by Royal Australian Navy warships in 2001 and 2002 and sent either to Nauru or Manus, an equally remote island in Papua New Guinea.
The vast majority of the asylum-seekers have either been granted refugee status and settled in other countries or sent back to their homelands.
Until recently, only two remained: Sagar and another Iraqi refugee named Mohammad Faisal.
But Faisal became suicidal and last month had to be evacuated to a hospital in Brisbane, Australia. His removal left Sagar a Shiite Muslim from Najaf, Iraq, as the last refugee on Nauru. He now feels alone and deeply depressed, according to human rights advocates.
He has set up a website to document his incarceration, www.leftonnauru.com, which includes pictures of the deserted refugee camp he inhabits.
"Can you imagine how horrible this nightmare is," he writes. "Just imagine that you are alone in a place where you can't even find anybody to talk to. Detention ... means that you do not own your life any more, or, in other words, you can't feel alive any more."
Sagar is stuck in legal limbo – although judged to be a genuine refugee by Australian immigration authorities, the country's intelligence agencies have ruled that he is "a risk to national security."
The Australian Security Intelligence Organisation (ASIO) has given no reason for its negative assessment and declined to answer questions on the case.
Sagar no longer has a valid visa, and Australia has so far refused to say whether it will pay Nauru a new visa fee for him.
Not only will Australia not accept Sagar as a refugee, the ruling that he's a security risk acts as a deterrent to any other nation throwing open its doors.
Opposition parties in Australia have called for the refugee camp on Nauru, which costs about $15 million a year to maintain, to be closed down.
"This is literally like something out of a Franz Kafka novel," Andrew Bartlett, the deputy leader of the opposition Democrats, said last month.
"They can't go back to Iraq, they can't go to any other country, they can't appeal the security assessment, and they can't even find out what it's about. I think that would drive anybody crazy. It's just a horrendous circumstance."
A high-profile Australian human rights lawyer, Julian Burnside, has launched a legal challenge to the Australian intelligence security assessment, demanding that it be made public.
"I agree with the label 'Kafkaesque.' I think what the Australian government is doing is nothing short of calculated cruelty," he says.
"It's a deliberate infliction of psychiatric harm. It may be that ASIO have either made a mistake, or overreacted to something they've learned about these men."
Even Nauru, which relies on the Australian-run detention center as its main source of income, is frustrated with the situation and wants to see Sagar released.
"We feel it's most unfair that his resettlement status continues to be left up in the air," Nauru's foreign minister, David Adeang, last month told the Australian Broadcasting Corporation. Australia should hold refugees on Nauru for "months rather than years," he said.
"It does not reflect on us very well as a government, as a country and as a people to be held responsible for somebody who, on our soil, turns out to be mistreated to the point he becomes suicidal," Mr. Adeang said.
Sagar lives in a small cabin outside the gates of the refugee camp. He is free to wander the island and has even worked part-time as a computer technician at a local college. Many Nauruans feel sorry for him.
"It's very surreal because he's walking among all these Australian officials and security guards and there's no feeling that he's a threat," says Susan Metcalfe, an Australian refugee advocate who's visited Nauru five times. "He even works in a Nauru government office and they are quite happy to sit down and have a cup of tea with him."
Sagar was studying microbiology in Iraq but says he had to flee in 1997 because of persecution by Saddam Hussein's Baathist regime.
"He swears black and blue that he has no idea why he was deemed to be a security threat. He can't even answer the charges against him because they haven't been disclosed. He's coming to the end of his ability to cope with the situation," Ms. Metcalfe says.
The United Nations High Commissioner for Refugees has tried for two years to find a third country willing to accept Sagar, so far without success.
"Australia's adverse security assessment has made it very difficult," says the UNHCR's Ariane Rummery. "We're very concerned about reports of his declining mental health. He's been there an awfully long time."
Nauru, dubbed Pleasant Island by early European explorers, was colonized by Germany in the 1880s. Since then it has had a distinctly checkered history.
Nauru was captured by Australian forces in 1914, and by 1920 fell under the joint trusteeship of Britain, Australia, and New Zealand.
In World War II, it was occupied by the Japanese, who deported 1,200 Nauruans to the island of Truk (or Chuuk), now part of the Federated States of Micronesia, where most starved to death.
After independence in 1968, Nauru earned billions of dollars from the mining and export of the purest natural phosphate in the world, which occurs in the center of the island. During the 1970s Nauruans enjoyed the world's second-highest per capita income, after Saudi Arabia.
But in a bizarre riches-to-rags story, most of that wealth was squandered through a series of spectacularly ill-conceived investment projects including, in 1993, the backing of a London musical about the love life of Leonardo da Vinci. The phosphate is expected to be exhausted within the next few years.