(CNN) At just 10 years old, Mizba Ahmed and her family fled persecution in Myanmar.

Boarding a smuggler's boat bound for Australia, she never imagined that instead of finding a better life, she'd end up spending 18 months in detention on the isolated Pacific island of Nauru.

"Nauru is the worst place I've ever seen for children," the 12-year old said.

Dozens of children like Mizba have been held for months, or even years, at an Australian-backed refugee processing center on Nauru, a tiny island measuring just 21 square kilometers or eight square miles.

CNN spoke to multiple current and former child detainees who describe the Nauru camp as a prison. Children live behind fences. They are searched when leaving or entering the camp, including when they go to school. They feel intimidated or harassed by the omnipresent security guards. But mostly these refugees describe the hopelessness of their lives and the vanishing dreams of an education and a future beyond the confines of this tiny island.

"It's not a crime to want to have a better life and future," said one 18-year-old girl who asked CNN not to reveal her name because she fears for her safety. "We are treated as prisoners."

Photos: Growing up in detention: The children of Nauru An image on the Facebook site "Free the Children NAURU," uploaded in November, 2015, shows a small child with a tally of how long they have been on the island. Hide Caption 1 of 10 Photos: Growing up in detention: The children of Nauru At the end of 2015, 537 people were being held in the Nauru detention center. Of those, 68 were children. Hide Caption 2 of 10 Photos: Growing up in detention: The children of Nauru At the end of 2015, of the 1,792 people being held in Australian immigration facilities, 23.2% had been held for more than 730 days, or more than two years. Hide Caption 3 of 10 Photos: Growing up in detention: The children of Nauru The children are being held on Nauru while their families' claims for asylum are processed. Many fled war-torn countries and entered Australian waters by boat. The Australian government says they'll never be resettled in the country. Hide Caption 4 of 10 Photos: Growing up in detention: The children of Nauru Australia reopened its controversial offshore processing centers in 2012, after a surge in arrivals of unseaworthy boats. In 2013, families with children were transferred to Nauru until their claims could be processed. Hide Caption 5 of 10 Photos: Growing up in detention: The children of Nauru The Australian government says the number of children in immigration detention centers dropped steadily between 2013 and 2015. However, numbers have leveled off since February 2015. Hide Caption 6 of 10 Photos: Growing up in detention: The children of Nauru On average, detainees spend 445 days in detention facilities while their claims are processed, according to government figures. Hide Caption 7 of 10 Photos: Growing up in detention: The children of Nauru The conditions endured by children at the Nauru detention facility have been the subject of a government inquiry, which investigated claims of sexual and physical abuse. Hide Caption 8 of 10 Photos: Growing up in detention: The children of Nauru The Moss Review found that many asylum seekers in the detention center were apprehensive about their personal safety. It found that some instances of sexual and physical assault were not being reported. Hide Caption 9 of 10 Photos: Growing up in detention: The children of Nauru The Australian government accepted all 19 recommendations made in the report. Immigration Minister Peter Dutton vowed to tighten security at the center, saying "I find the thought of anybody, in particular children, being sexually assaulted

completely abhorrent." Hide Caption 10 of 10

Stopping the Boats

As Europe struggles to cope with the flood of migrants and refugees arriving by boat, Australia has for years embarked on a controversial and unusual policy. It intercepts boatloads of migrants and refugees and then places them in detention on small, relatively poor Pacific island nations.

Between 2007 and 2013, the Australian government says at least 1,200 people lost their lives trying to make the journey over water, and thousands more ended up in Australia's immigration system. The government says it is trying to send a clear message to potential asylum seekers that if they board a boat there is no hope of settling in Australia.

Since 2012, refugees who arrive by boat are sent for processing to either the Nauru camp or one on Manus Island, in Papua New Guinea. If their asylum claims are granted, they are settled in those countries or some have the option of moving to another country: Cambodia.

It's a deterrent the government argues has worked.

"The Coalition Government has stopped the perilous flow of people smuggling ventures. There has not been a successful people smuggling venture to Australia in the last year," an Australian government spokesperson said in a statement to CNN. The Australian immigration minister declined CNN's request for an interview.

The statement continued, "Stopping the boats has enabled this Government to return integrity to Australia's humanitarian and refugee programme."

Cockroaches and Forgotten Dreams

As of the end of December, Australia government records say that 537 people were in detention on Nauru, including 68 children. Their nationalities read like a list of the world's major conflicts zones, including Iran, Afghanistan, Iraq and Syria. The Nauru government operates the detention center with support from Australia and private contractors.

Families in Nauru live in tents without air conditioning in a country known for year round sweltering heat. Photos provided by refugees show moldy tent roofs and rusty fans. Three refugees complained to CNN of rats in their tents.

"We can't sleep at night because of the cockroaches," Mizba said.

Another former detainee said he felt the guards disrespected the asylum seekers and treated them like criminals. "We are always being watched," said the teenager, who also asked that CNN not reveal his name for fear of retribution.

He and other refugees said the boredom and lack of educational opportunities led to widespread depression among the teenagers, even suicidal behavior. "My life doesn't mean anything inside detention," he said.

Security at the camp has been a constant problem. A 2015 Australian government report documented accusations of sexual and physical assault at the processing center, including cases involving children. The accusations were directed both at other detainees and at center staff members. The Australian government says it is implementing the recommendations made in the report.

CNN reached out by phone and email to the Nauru Government Information Office to ask them about conditions at the refugee center. They did not respond. The Australian government said the management of the center is the responsibility of the Nauru government.

An inquiry by the Australia government's own human rights commission in 2014 concluded that "children on Nauru are suffering from extreme levels of physical, emotional, psychological and developmental distress." The inquiry recommended all children and their families be removed from Nauru and settled in Australia within four weeks of the report.

Many of the children in Nauru are already trying to overcome the trauma of being persecuted in their home countries and making the treacherous sea journey to Australia. One of the girls CNN spoke with spent hours in the open water after her boat sank en route to Australia.

"I gave up. I was thinking that we were all going to die, it's just a matter of time," she said. The Australian Navy rescued her family and many others on board, but five of the other passengers drowned, she said.

Australian Senator Sarah Hanson Young is a vocal advocate of shutting down the Nauru facility. "There's absolutely no way the Australian government can justify keeping, particularly families, women and children in these camps," she said. "They can't guarantee their safety."

No journalists are allowed in. There is very, very little information let out of the camp and staff who work at the center are essentially gagged. Senator Hanson Young

The Australian and Nauru governments make it very difficult for journalists to see the detention center firsthand. The Nauru government charges media an A$8,000 dollar (around US$5,800) nonrefundable visa fee per application. The Australian Immigration department requires journalists who wish to apply to visit Australian detention centers to first sign a form saying they will not interview any detainees, and that they will submit all their content to the government for screening. They forbid pictures, video and audio records of detainees. The government says this is in order to protect their privacy.

CNN is unwilling to accept these conditions, so we've interviewed seven current and former camp residents remotely about what it's like for children to live in this detention center.

Senator Hanson Young believes there is a culture of secrecy and coverups within the operation. "No journalists are allowed in. There is very, very little information let out of the camp and staff who work at the center are essentially gagged," she said.

The Australian government has repeatedly said access to the Nauru center is up to the Nauru government.

The Nauru government has gone on record defending its restrictions on allowing foreign journalists to visit the island.

In a press release posted on the government's website last October, Justice Minister David Adeang argued, "if the country allowed journalists to wander the small island, refugees who are now living peacefully would... start to protest and riot for the cameras and there would be chaos that the nation's police force would struggle to maintain."

Opening the Camps

In October, the Nauru government, which operates the refugee center, announced it was ending the forced detention and creating an open center. "All asylum seekers are now free to move around the island at their will," the government wrote in its initial release.

The refugees still inside the camp say this change has made little difference to their lives. Many living in the camps have been waiting years for a decision on their asylum seeker status. While they wait, they are not allowed to take money or food out of the detention center. They also don't feel comfortable leaving the camp at night because of safety concerns.

Prior to this year, the Australian government operated a school specifically for the asylum seeker children. Now that school has been shut and students have been urged to enroll at the public school in Nauru. The children say they feel like they lost the one place within the camp where they felt happy and secure.

Several have stopped attending the local school because they say they were harassed by the other students. With nowhere to go all day, they say they suffer from boredom and depression. One 15-year-old girl says she locked herself in a bathroom to escape the advances of a male student. Ever since then she stopped going to school. Now she says she cries all the time in her room. And she watches her mother cry.

"I want to become something and here I am doing nothing," she said. She desperately wants to go to school and become a doctor. But that dream feels very far away after years spent in a detention camp in the middle of the Pacific Ocean.

Prior to her departure from Myanmar, 12-year-old Mizba Ahmed said she also dreamed of one day becoming a doctor. After more than a year in detention on Nauru, and after abandoning the island's public school system, she says she has given up her hope of one day practicing medicine.

"Living here, no school, I don't think I can become anything else. There's no education here," she said.

And yet, Mizba says she still clings to the hope that prompted her family to board a smuggler's boat two years ago.

"We just want to go to Australia," she said.

The scars of her time on Nauru have not been enough to destroy her faith in what Australia has to offer.