Flat-Earthers also assert that no one is allowed to fly over or explore Antarctica, despite contrary evidence. According to them, all photos and videos of ships sinking under the horizon and of the bottoms of city skylines and clouds below the horizon, revealing the curvature of the Earth, have been manipulated, CGI, or somehow faked. Therefore, regardless of any scientific or empirical evidence provided, flat-Earthers stubbornly conclude that it is fabricated or altered in some way.[42]