From the discovery of radioactivity to quantum physics, through Einstein's theory of relativity, Bohr's atom, and the use of X-rays to study the properties of solids. These are just some of the fascinating discoveries that physics has made over the past 150 years, which we revisit in this book. We will discuss elementary electric charge, spontaneous radioactivity, X-rays, the Zeeman effect, the Michelson-Morley experiment, liquid helium, the Bohr atom, X-ray diffraction, energy quantization, and the photoelectric effect. At the end of the book, there is a list of Nobel Prizes in Physics awarded up to the present day.