Elcho Island runs roughly 60 kilometres from end to end and only six across at its widest, the largest of the Wessel Islands group at the eastern edge of Arnhem Land. Galiwin'ku, the main community, sits near the southern tip - 150 kilometres north-west of Nhulunbuy and some 550 kilometres from Darwin across open water and bush. Around 2,200 people live here, the overwhelming majority Yolngu, and this is the largest and most remote Aboriginal community in north-east Arnhem Land. The island holds extraordinary linguistic depth: dozens of hereditary clan groups, or mala, and more than a dozen languages still spoken, with Djambarrpuyngu serving as the lingua franca. This is saltwater country in the deepest sense - land and sea bound together in law, kinship, and song, knowledge carried unbroken across generations.

In 1942 the Methodist Overseas Mission established a settlement at Galiwin'ku, led by the lay missionary Harold Shepherdson - known to Yolngu as Bapa Sheppy. The mission ran the place until 1974, when it passed to Yolngu self-management. But the defining moment came in 1957, and it belonged entirely to the Yolngu. Feeling their law dismissed by the mission, senior leaders including David Burrumarra made an extraordinary decision: they would publicly reveal madayin, sacred objects ordinarily seen only by initiated men, displaying them in the open. The Adjustment Movement, as it became known, was both an act of diplomacy and a declaration. It asserted that Yolngu law was coherent, enduring, and the equal of anything the newcomers had brought - a sovereign people choosing, on their own terms, what to share.

Music runs through Galiwin'ku like a tide. Geoffrey Gurrumul Yunupingu left the band Yothu Yindi to return home to Elcho, co-founded the Saltwater Band, and then recorded solo albums that made him the most celebrated Aboriginal musician of his time before his death in 2017, aged just 46. He was not the island's only gift to the wider world. The island helped inspire 'My Island Home', written by Neil Murray for the Warumpi Band and later sung by Christine Anu at the closing of the Sydney Olympics. And the Djuki Mala dancers - the 'Chooky Dancers' - filmed themselves performing to Zorba the Greek in 2007; the clip drew hundreds of thousands of views in weeks and carried them onto stages across Australia.

At Shepherdson College, around 700 students from birth to year 12 learn in both Djambarrpuyngu and English - an approach Yolngu call 'both-ways', balancing their own knowledge with Balanda, the white world's. Down at Elcho Island Arts, community-run since 1992, senior artists like fibre weaver Mavis Warrngilna Ganambarr and Morning Star Pole custodian Gali Yalkarriwuy Gurruwiwi turn ancestral knowledge into work that sells worldwide. The island guards its own threshold: visitors need a permit through the Northern Land Council, alcohol is restricted, and there is no ordinary petrol. None of this is quaintness. It is a living culture deciding, as it did in 1957, exactly how it meets the outside world.

The sea here has always carried strangers as well as song. For generations before any European arrived, Makassan sailors from the islands of what is now Indonesia came each year on the monsoon to harvest trepang, the sea cucumber prized in Chinese kitchens, trading and intermarrying with Yolngu and leaving words behind in the languages still spoken today. In 2018 a small copper coin turned up on an Elcho beach, possibly minted by the medieval Kilwa Sultanate of East Africa - an echo, however faint, of how far the currents of the Arafura Sea once reached. Long before the world arrived by ship or screen, Galiwin'ku was already connected to it.