This talk aims to show students and pupils the interconnection between physics, chemistry, biology and their enormous influence on our everyday lives, which we are often unaware of. The nitrogen atom is chosen as the medium - we will show how important it is for our lives - how it influenced the origin of life and its development on Earth, how it protects us, in what molecules it is indispensable for living organisms, how it is used in food processing and how historians and palaeontologists use it without knowing it, how it has become responsible for the exponential growth of the Earth's population, why it is found in explosives and how it has become essential for the development of smartphones, laptops and white LED lighting. The talk is accompanied by small experiments.