Last Friday afternoon, the guests of the Mainz Science Tram experienced an entertaining and informative ride. Various scientists from Mainz introduced them to very different fields of research on the tour through Mainz. Professor Achim Denig from the Institute of Nuclear Physics was also on board with his lecture "Quarks & Co - The fabulous world of the smallest particles". With a wink, he pointed out to the audience at the beginning that the lecture was of course not about (food) quark, but about the building blocks of which all matter, whether humans, galaxies or food quark, is composed. In the past decades, nuclear and particle physics have succeeded in identifying the basic building blocks of matter - the so-called elementary particles - and in describing their interaction with each other in the Standard Model of particle physics. These elementary particles include quarks, which exist in six types and form the basis for protons and neutrons.