Australia’s submerged northwest continental shelf, which connected the Kimberley and western Arnhem Land, was a vast and habitable realm that covered nearly 390,000 square kilometers. This area was likely a single cultural zone with similarities in technology, art, and language. Archaeological evidence from underwater sites around the world, including Australia, shows that humans once lived on continental shelves. A new study reveals the complex landscape of the Northwest Shelf, which existed before the last ice age ended and sea levels rose. The landscape included archipelagos, lakes, rivers, and a large inland sea. The region could have supported a population of 50,000 to 500,000 people at various times over the past 65,000 years. As sea levels rose, people were forced to retreat from the submerged landscape. This research highlights the importance of Indigenous knowledge and experience in adapting to changing climates.