The Al Asad air base is so vast that, after the US invasion, it had cinemas, swimming pools, fast food restaurants, and - not one - but two internal bus routes.
It was built in the 1980s for the Iraqi military, in desert around 100 miles west of Baghdad.
But after the US invasion in 2003, it became one of the biggest bases for American troops - and was quickly transformed.
"It's right in the middle of the desert, and surrounded on all sides by scrublands and desert and rocks," Oliver Poole reported for the BBC in 2006.
"As you emerge into the American section, you come across much better roads... in many ways they've tried to recreate the set-up of a modern US suburban town."
The facilities were so impressive, some US troops even called it "Camp Cupcake".
As the US withdrew from the base in 2009 and 2010, it was handed back to the Iraqis. But, as the Islamic State group gained control of surrounding Anbar province, the base came under attack.
In 2014 - as IS encircled - the BBC's Quentin Somerville gained access via an Iraqi military plane.
"Reminders of American occupation are everywhere - spent artillery shells and dusty accommodation quarters, with uneaten ration packs strewn across the floor," he reported.
After the US returned to Iraq to fight IS in the same year, the base was secured and rebuilt.
However, with far fewer troops, one airman noted in 2017 that "it only offers a fraction of the comforts it once did".
On 26 December 2018, President Trump visited troops at the base.
"The men and women stationed at Al Asad have played a vital role in the military defeat of ISIS in Iraq and in Syria," he told them.
But afterwards, he said he feared for his wife's safety during the visit. "If you would have seen what we had to go through," he told reporters.
In November last year, Vice-President Mike Pence also visited the base for Thanksgiving.
It's thought there are around 1,500 US and coalition troops at Al Asad, and around 5,000 US troops in the country in total. This week, in a non-binding vote, the Iraqi parliament voted to expel them.
In response, President Trump brought up the cost of the Al Asad air base.
"We have a very extraordinarily expensive airbase that's there," he said. "It cost billions of dollars to build. Long before my time. We're not leaving unless they pay us back for it."
The other base that was attacked was in Irbil, the capital of Iraq's relatively stable Kurdistan region.
In September, the US Army said it was home to "more than 3,600 military and civilian personnel from 13 different nations".
The base is used to train local forces. Last month, US Central Command reported that the first female military instructors in the region had graduated from Irbil.
How long the US will stay in Iraq, though, is uncertain. Only this week, Defence Secretary Mark Esper was forced to deny the US was withdrawing troops from the country.