The megameter (Mm) is a unit of length in the International System of Units, defined as 106 meters using the SI prefix system. Megameter is rarely used. It could be used to specify long distances around the world as well as specifying the sizes of the worlds. For example the distance from London to New York is 5.57 megameters, and from Tokyo to Los Angeles is 8.83 megameters. The widest country of Russia spans about 9 megameters while the perimeter of Russia is about 20 megameters. The diameter of Earth is 12.742 megameters while the circumference of Earth is about 40 megameters. The Moon has a diameter of 3.474 megameters while Jupiter, the biggest planet in our solar system, has a diameter of 139.822 megameters.