Mabo Day is observed in Australia every June 3, commemorating Torres Strait Islander Eddie Koiki Mabo and his campaign for indigenous land rights. This day marks the anniversary of the High Court of Australia's landmark decision in 1992, which overturned the legal fiction of terra nullius, a concept that had defined land ownership in Australia since the arrival of James Cook in 1770. Eddie Mabo, who passed away in 1992, initiated this campaign, and his wife, Bonita Mabo, proposed the establishment of Mabo Day in 2002, coinciding with the 10th anniversary of the court's decision. The Aboriginal and Torres Strait Islander Commission launched a petition in 2003 to make Mabo Day a public holiday, and efforts continued into 2010 to elevate it to a national holiday. The significance of Mabo Day is recognized as greater than that of the Queen's Birthday, reflecting its importance in addressing the historical injustices of colonization.