Maxwell's equations and the discovery of electromagnetic waves changed the world. Can you imagine how our everyday life would be without telephone, radio, television, mobile phones and internet? It's thanks to Maxwell's equations that we understand what electromagnetic waves are and how they are generated, propagated and detected. These equations can even change our perception of nature when they are really understood, but their power and elegance is completely appreciated when they are expressed in differential form. Moreover, this form is extremely useful dealing with some issues, such as the propagation of electromagnetic waves.