The universe is, in the plain words this film opens with, absolutely huge, and it asks viewers to imagine driving down a road to grasp just how huge. Produced by the Royal Observatory Greenwich, the film assembles footage from the Hubble Space Telescope, the Chandra X-ray Observatory, and the James Webb Space Telescope alongside interviews with working astronomers to explain how anyone measures something with no edge to stand on. It walks through the actual techniques: reading the cosmic microwave background for the universe's oldest light, tracking galaxy clusters to map large-scale structure, and using gravitational lensing, the bending of light around massive objects, to weigh things that give off no light at all. Analogies do a lot of the work throughout, scaling distances and sizes down to something a human body can picture rather than just a number on a screen. The film also gives time to more speculative ideas circulating in cosmology, including the multiverse hypothesis and a cyclic universe, without treating them as settled. It ends on how much of the universe's size and shape is still genuinely unknown.