There are no borders for light. It is only limited by the Earth's curved surface and diverse terrain. Even though there are no artificial light sources in protected areas, such as El Teide National Park, and even if there is no Moon in the sky, there is no guarantee that the sky is dark.

Do we really need light twenty-four hours a day, and at night, when the majority of people are asleep? Is light really a common denominator for safety, carefreeness, ideas, discovery, etc?