Compass, which is called 指南针 (zhǐ nán zhēn) in Chinese, is an instrument used to show direction. The magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty (since about 206 BC). The compass was used in Song Dynasty China by the military for navigational orienteering by 1040–1044, and was used for maritime navigation by 1111 to 1117. Do you know what does the ancient 指南针 look like? How did it work?