A saucer-shaped, futuristic building built on the surface of the moon. Supported by several steel pillars, the building seems to float in midair. A building that can be extended forever from the center outward in a spiral shape. It is already about 1 km in diameter. There is no air outside, so people can only live in buildings. Thousands of stars in the sky. The blue earth is also visible. In the distance, craters on the moon can be seen, but no large mountains are visible.