What is space?

This is not a philosophical question. I actually want to talk about what space is as can be translated into pictures. For a photo documentary project that I have been thinking for several years.

Apart from the common terms of "empty space" that suggests space as a container for activities to go on and objects to be stored, space is an ongoing result of a series of human activities. A high-rising building in the US, and also many other parts of the world, usually has an elevator, allowing people to go up and down in an efficient manner. Its commonplace existence often hides its important roles of making the space: that a building with elevator makes the building into a different set of social uses and time concepts. Even more specific, but in no way less important, the panel of an elevator with the sign language for the visually-impaired  makes it accessible to that group of people, thus, making the whole building mediating a different level of accessibility.