How can we map the distribution of galaxies over thousands of millions of light years? What does the Universe look like on these scales? How did get to look like that? And how do we know?This talk will explain how astronomers and cosmologists have come together over the past couple of decades to make huge surveys of the Universe, revealing the existence of a complex but beautiful `Cosmic Web' with vast chains of galaxies strung out around immense dark voids. These observational breakthroughs have been mirrored by advances in theory and computer simulation that allow us to understand how this amazing structure was born 14 billion years ago in the Big Bang and has been growing and evolving ever since.Free and open to TY, 5th and 6th year students, this talk will be of particular interest in those interested astronomy, space, physics and the Universe itself!