What is space? This fascinating journey of exploration begins in our own minds - the space within our brains. We discover how space is used in sign language and in architecture, before moving on to the virtual space created in an imaginary computer-generated world. The delineation of space has been important throughout human history, and we look at how boundaries have been mapped in the past, and how they remain politically important today. Finally, we travel into outer space, to look at human exploration and the ultimate nature of space and the universe.