For the Marra, Gurrululinya is not a backdrop but a presence. Sixteen sacred sites on the island are registered with the Northern Territory's Aboriginal Areas Protection Authority, a measure of how densely meaning is layered across so small a place. One tradition holds that this is the resting place of the Kangaroo Dreaming, an ancestral being that travelled across the desert and finally lay down here, on the island's sand. Another speaks of a poisonous she-oak that may strike down those who come where they should not. These are not quaint legends; they are living law, the kind of knowledge that defines who may visit, what may be touched, and how the country must be treated. To the Marra, the island has a will of its own.

The waters around Gurrululinya are as alive as the island is sacred. Seagrass meadows ring its shores, and they draw three species of sea turtle to nest on its dunes, among them the olive ridley and the flatback, which haul ashore under cover of darkness to bury their clutches in the warm sand. Herds of dugong move through the shallows, grazing the same meadows; pods of dolphins follow the same currents. The island's interior teems with northern brown bandicoots, while silver gulls wheel above in noisy colonies that wheel and settle and rise again. For the critically endangered curlew sandpiper and the great knot, both long-distance migrants that arrive exhausted from the far side of the world, and for the strange, ancient freshwater sawfish, these wetlands are a feeding and breeding refuge. It is a small island carrying an outsized share of the Gulf's wild abundance, a single low rise of sand that functions as a nursery for some of northern Australia's most threatened animals.

In 2011, the island's quiet was nearly broken. Western Desert Resources and its partner Sherwin Iron unveiled a plan to pipe slurry from their Roper Bar mine out to Gurrululinya, where it would be processed and loaded onto barges bound for steel mills in East Asia. The following year Maria Island was folded into the new Limmen National Park, yet the arrangement carved out significant areas for mining exploration. Then the iron ore market slumped, and in 2014 both companies collapsed. Later a Dubai firm, Al-Rawda Resources, floated reviving the scheme, proposing a barge-loading facility on the wetlands. The Marra community pushed back, warning that such infrastructure would foul what remains a pristine reserve. For now, the island endures untouched.

The first Europeans to see this coast were the Dutch, and they got it wrong. Sailing past, they marked Gurrululinya not as an island at all but as a cape, a mistake that survived until the Englishman Matthew Flinders came through in late December 1802 and sailed clean around it, proving it was ringed by water. It was a small correction on a chart of a vast and barely known coast. But it is a fitting one for a place that has so often been misjudged from a distance, dismissed as a featureless lump of sand when it is, to those who know it, a cathedral of country, fully alive and fully claimed.