The Martian Cylinder, more commonly known as just the Cylinder, was a transport used by the Martians in their attempts to invade Earth. Using the Great Gun, the Martians fired their Cylinders from Mars and they reached Earth in ten Earth days. The Cylinders were gigantic in size and their impact with the Earth left huge craters which the Martians used as base camps. The invasion party was made up of a total of ten Cylinders. Each Cylinder held five Martians, five Tripod Fighting Machines, two Handling Machines, and the materials required to construct one Martian Flying Machine.