The Great Wall of China, often cited as visible from space with the naked eye, is actually difficult to see due to its width and blending with the surrounding terrain. Astronauts and space agencies have consistently reported that it is nearly impossible to distinguish without optical aid.

However, other large man-made structures are visible from space. Cities, especially at night due to their lights, are easily observable. Large-scale agricultural features, such as the greenhouses in Almería, Spain, and certain open-pit mines, are also visible due to their extensive area and high contrast with the surrounding landscape. These structures appear as distinct patterns or blotches, making them detectable without optical aid. Additionally, large-scale land reclamation projects like the Dubai Palm Islands can be seen from space due to their massive size and artificial geometry, creating a noticeable contrast with the surrounding ocean.