Sir David Attenborough is in the Swiss Jura Mountains to discover the secrets of a giant. Beneath his feet lies a vast network of tunnels and chambers, home to a huge empire of ants. It is believed to be one of the largest animal societies in the world, where over a billion ants from rival colonies live in peace.

After a life spent travelling the globe, the world’s most famous naturalist turns his attention closer to home to explore the wildlife of England’s iconic capital. Having lived in London for 75 years, Sir David has an intimate knowledge of the city’s natural history, and there's no better guide to introduce us to its most spectacular wildlife secrets. Captured over his centennial year, this personal and poignant film is a timely insight into how cities can become homes for wildlife as well as ourselves.