On Australia Day 1966, nine-year-old Jane Beaumont, seven-year-old Arnna Beaumont, and four-year-old Grant Beaumont took a familiar bus trip from Somerton Park to Glenelg Beach near Adelaide. They were seen by witnesses, possibly in the company of an unidentified man, and then vanished into one of Australia's most enduring missing-child cases. Decades of searches, letters, suspect theories, and excavations have produced no confirmed trace of the children, and the case remains unresolved.