For complicated reasons to do with war and politics, the only way in and out of the enclave controlled by Syria's Kurds is on a rusty iron boat that ferries passengers across the Tigris River from Iraq. Late last year, photographer Alice Martins and I boarded one of those boats to head for the front lines in the fight against Isis (Islamic State).
The journey took us more than 640km across the emerging Kurdish region in northeastern Syria, mostly desert land that covers as much as a third of the country.
Here, the Kurds have taken advantage of the chaos of Syria's war to forge a functioning state within a state that has collapsed in many other parts of the country. They are also expanding the frontiers of their region, to the west and the south, into lands that are traditionally Arab. The Kurds have named it the North Syria Federation.
These new frontiers were our destination: the outskirts of Raqqa, Isis' capital; and the town of Manbij, which lies just to the west of the Euphrates River.
The first few hours took us through some of the most peaceful parts of Syria. In 2012, the Kurds took over a big swath of territory without a fight after the Syrian Government withdrew. The towns of the far northeast are getting on with life. Shops and markets are open, streets are crowded.
As we moved farther west, evidence of the war began to mount. Destroyed, abandoned villages dot the desolate desert highway. The billboards of the portraits of the dead become more crowded with faces and names. These are areas the Kurds have battled fiercely to control, first against the Free Syrian Army and later Isis.
We arrived in Kobane, the town that stood up to Isis in 2014 . Today it has the busy, determined feel of a community trying to rebuild. But the scale of the damage was vast; and the trauma, immense. In places, families are living in their wrecked homes, held together by patched concrete. Whole neighbourhoods are eerily empty, still in ruins. Their residents have become refugees.
The Raqqa front lies about an hour-and-a-half drive away to the south, down more empty desert roads, past more smashed homes and villages, past vast concrete silos that once stored grain and have been turned into military bases. Now Kurdish fighters, aided by local Arab recruits, still wage an offensive to encircle and isolate Raqqa.
When we visited, the fighting had paused at an abandoned, heavily mined town called Tal Saman. Nearby, civilians fleeing areas that were expected next to be targeted were heading north, in trucks and cars piled high with possessions. People whose villages had been freed from Isis control were hauling their possessions back.
We headed farther west, across the Euphrates, to Manbij. It was startling to come across the vast expanse of water, sparkling in the bright winter sun, flocks of birds circling overhead.
Manbij brings more reminders of the toll of war. The Kurds and their Arab allies captured the town from Isis after a bitter, two-month fight, and in the process much of it was destroyed. Collapsed masonry spills onto the streets. Isis iconography still adorns buildings, parks and traffic circles.
We visited one neighbourhood where a US airstrike knocked out what appeared to be an entire block. The target was an Isis fighting position in a four-storey building that no longer exists. Neither do any of the surrounding homes. One house collapsed on a family taking shelter there, killing nine of them, neighbours said.
Residents said they are glad Isis has gone, but they were fearful of talking too much about the new circumstances. The town has changed hands four times since 2011, from the regime, to rebels, to Isis and now to the US- and Kurdish-allied Arabs. Who knows who will come next, mused a pharmacist in his shop in one of the streets that have come back to life.
The war isn't very far away. About 30 members of an extended family who had tried to escape a nearby front line by taking a detour across farmland had crossed into a minefield. Half of them were blown up, and the hospital's sparse rooms were filled with bleeding, maimed people. A girl called Aya who could have been no more than 5 lay on a grubby sheet, her body riddled with shrapnel from the waist down. Doctors said she was expected to lose both of her legs. On a nearby bed was her father, unconscious under a blood-specked blanket. When we returned two days later, he had died.