Wills knew that he was fading fastest. On 26 June, he decided the only honourable thing to do was to sacrifice himself to save his companions. ‘Without some change,’ he wrote, ‘I see little chance for any of us.’ In 1860, an eccentric Irish police officer named Robert O'Hara Burke led a cavalcade of camels, wagons and men out of Melbourne. Accompanied by William Wills, a shy English scientist, he was prepared to risk everything to become the first European to cross the Australian continent. A few months later, an ancient coolibah tree at Cooper Creek bore a strange carving: Dig Under 3ft NW. Burke, Wills and five other men were dead. The expedition had become an astonishing tragedy. Sarah Murgatroyd reveals new historical and scientific evidence to tell the story of the disaster with all its heroism and romance, its discoveries, coincidences and lost opportunities.