K'gari (formerly known as Fraser Island) in Australia is the largest sand island in the world. It stretches over 75 miles (120 km) long and is 14 miles (22 km) wide. Remarkably, despite being composed entirely of sand, the island supports lush rainforests growing at high elevations—a phenomenon that occurs nowhere else. The sand is held together by a unique fungi-rich soil that allows trees to thrive. It is also home to more than 40 'perched' lakes, which are lakes made entirely of rainwater sitting in depressions in the sand dunes. This UNESCO World Heritage site is a testament to the strange and beautiful ways nature adapts to extreme environments.