Authorities all over the world say UFOs are real, but what are they, and are they a threat? This series examines the best and latest evidence caught on camera.
Humanity's drive to push the bounds of the known world sometimes results in tragedy - but science still remembers the breakthroughs.
Throughout history certain civilisations, events and objects have fascinated and inspired us, causing those involved to dig deeper and go further on a ceaseless quest to be the first to finally uncover the truth.