Members of the Flat Earth Society and other flat-Earthers claim that NASA and other government agencies conspire to delude the public into believing the Earth is spherical. According to the most widely spread version of the current flat-Earth theory, NASA is guarding the Antarctic ice wall that surrounds Earth. Flat-Earthers argue that NASA photoshops its satellite images, based on observations that the color of the oceans changes from image to image and that continents seem to be in different places. The publicly perpetuated image is kept up through a large-scale practice of "compartmentalization", according to which only a select number of individuals have knowledge about the truth.