If someone asked you to name the world’s driest continent, what would you guess? Would you be surprised to know it is Antarctica? Even though most of Antarctica is covered with ice and snow holding eighty percent of the world’s fresh water, the continent is, by definition, a desert. Antarctica accumulates on average fewer than 2 inches (5 cm) of water equivalent per year—that is just slightly more than what the Sahara Desert receives. You might wonder how, if Antarctica receives such a small amount of precipitation each year, it could accumulate eighty percent of the world’s fresh water. The snow and ice that forms the Antarctic Ice Cap accumulated over millions of years.