Space exploration has reached its golden age. Over the last few decades our view of the cosmos has fundamentally changed due to advances in the design of telescopes. Throughout history, telescopes have led to significant shifts in our sense of our place in the universe. Today, the development of new telescopes mean we are on the cusp of a new era of discovery... The latest telescopes now allow astronomers to observe objects and events formerly hidden from view in the 'invisible universe' - the vast realm that exists beyond the visible part of the spectrum of light. It is here that breathtaking new discoveries are being made, often by chance - giant black holes; supernovas; entire new galaxies - discoveries that completely alter our understanding of the universe. From NASA's Sofia infra-red telescope which scans the sky at 45,000 feet in the air, from the back of a converted plane, to the telescope designed to orbit the Earth beyond the moon, Horizon takes a look at the telescopes opening this new window outside our world. These machines are among the most advanced ever built: triumphs of ambition and design, engineered to function perfectly in some of the harshest places on Earth - and beyond. From bizarre structures for detecting elusive cosmic rays to epic shrines to science high on desert mountains, the latest telescopes will change our view of space forever.