It's the sixth-largest country in size, but has the lowest population density in the world — less than one person to a square mile (2.5 square kilometers). It boasts what is considered the world's oldest civilization; the Aboriginal society dates back some 50,000 years. Yet, the area's first modern community was only established in the 18th century and the commonwealth was formed just a century ago. Ninety-five percent of the world's opals and much of the world's wool and beef are produced here. It has the world's largest oyster, the world's longest earthworm and the world's heaviest crab. The world's longest continuous fence keeps the dingos from attacking the sheep. Good onya, Australia! Enjoy today's Australia Day celebrations!