Taking a small, chartered plane to the remote Cuban coastline, Australian lawyer Stephen Kenny visited Guantanamo Bay five times.
He was representing Adelaide man David Hicks, who was detained on the United States naval base from January 2002 until May 2007.
Access to the military prison, best known for holding terror suspects, was rare, even for lawyers.
And what Mr Kenny witnessed there was "appalling".
"Initially they held the detainees in cages," he told the ABC.
"They were effectively like dog pens, with a concrete floor, a corrugated iron roof and cyclone wire surrounds."
Guantanamo Bay has drawn worldwide controversy over alleged violations of torture and abuse of detainees.
Previous US presidents have reduced inmate numbers and sought to shut it down.
Now Donald Trump has not only vowed to keep it open, but plans to send 30,000 migrants there.
What is Guantanamo Bay?
Mr Kenny's first impressions of Guantanamo was that it was small and "very basic" with limited infrastructure.
The site relied on a desalination plant for water, which would often have issues, and phone connection was difficult.
He said it was hard to imagine thousands of detainees being held there.
Facilities were generally only designed for about 200 people.
"I think there would be a need for considerable building work to be done before they can house 30,000 detainees there, unless they're only held there for a very short period of time," he said.
[map]The military prison at Guantanamo Bay opened in January 2002, following the September 11, 2001, attacks on the US — the deadliest terrorist incident in the country's history. The attacks, commonly known as 9/11, involved a series of coordinated suicide missions.
Since early 2002, about 800 people from several countries were detained on suspicion of militant activity or terrorism-related offences.
Only 15 inmates currently remain, including accused 9/11 mastermind Khalid Sheikh Mohammed.
Former president Joe Biden released a number of detainees toward the end of his term.
Guantanamo Bay has long been condemned by human rights groups for alleged human rights violations, including the use of various forms of torture during interrogations.
Mr Kenny was aware of detainee mistreatment during interrogations.
"They used advanced interrogation techniques like stripping people naked, chaining them to the floor and putting on the air conditioning, playing loud music and flashing lights," he said.
While Guantanamo Bay is best-known for its military prison, for decades it has also held migrants in a separate facility.
The Guantanamo Migrant Operations Center (GMOC) is used for people intercepted trying to illegally reach the US by boat, most are from Haiti and Cuba.
'A tough place to get out of'
The migrant centre is reported to have capacity for about 130 detainees.
Mr Trump signed an executive order this week to begin preparations to expand on the existing centre and create a "30,000 person migrant facility".
The US president said it would be used to "detain the worst criminal illegal aliens threatening the American people".
His defence secretary, Pete Hegseth, told Fox News that migrants would not be kept where the remaining 9/11 detainees were held, and that a golf course could be used to build facilities.
Mr Trump has made the deportation of migrants a central part of his campaign and presidency.
At the signing ceremony, he noted that Guantanamo was "a tough place to get out of".
Mr Kenny said the situation would be "extremely isolating".
"It would be very difficult for them to access their legal rights, and for family and lawyers to have any real contact with them," he said.
"You won't be able to get access without the assistance of the military."
Migrants describe 'prison like' conditions
Little is known about Guantanamo's migrant centre.
In a 2024 report, the International Refugee Assistance Project (IRAP) accused the US government of secretly holding migrants indefinitely in "inhumane" conditions.
It said there was "virtually no publicly available information" on the centre, and freedom of information requests about the detention of migrants and refugees were still pending.
The IRAP said staff and detainees described "prison-like" conditions, reporting that buildings were dilapidated and had mould and sewage issues.
Refugees were regularly confined to their rooms for weeks at a time, and denied confidential phone calls, even with their lawyers, the report said.
Deepa Alagesan, a senior supervising lawyer with the IRAP, said the group estimated the centre was used to hold a small number of people in the "double digits".
She said a significant increase in migrants being sent to Guantanamo was "definitely a scary prospect".
President sends 'a clear message'
US military bases have been used repeatedly since the 1970s to accommodate the resettlement of waves of immigrants from Vietnam, Cuba, Haiti, Kosovo and Afghanistan.
But questions have been raised about the plausibility of Mr Trump's Guantanamo plans.
He has vowed to deport millions of people living illegally in the US.
The current Immigration and Customs Enforcement budget only has enough funds to detain about 41,000 people.
Mr Kenny said regardless of the number of migrants that might end up at Guantanamo, he was concerned about their hopes for release.
"Legal representation is very difficult, even for the detainees, it required quite a bit of dedication from the lawyers," he said.
Vince Warren, the executive director of the New York-based Center for Constitutional Rights, said Mr Trump's decisions "should horrify us all".
Mr Warren's advocacy group has represented dozens of men detained at the base since the terrorist attacks on the US on September 11, 2001.
Mr Trump's order "sends a clear message: migrants and asylum seekers are being cast as the new terrorist threat, deserving to be discarded in an island prison, removed from legal and social services and supports," he said.
ABC/Wires
