Devon Island in the Canadian Arctic is the largest uninhabited island on Earth. It is approximately the size of Croatia (over 21,000 square miles). The island is so desolate and has a climate so similar to Mars that scientists from NASA use it as a testing ground for space missions and rovers. It features the Haughton Impact Crater, a 14-mile-wide crater formed by a meteorite 39 million years ago. Despite its size, no one lives there permanently due to the extreme cold and rugged terrain. It is a 'polar desert' that provides a unique opportunity to study planetary geology and extremophile life right here on Earth.