  In these lecture notes, prepared for the Microswimmers Summer School 2015 at
Forschungszentrum Juelich, I discuss the well known Vicsek model for collective
motion and its main properties. In particular, I discuss its algorithmical
implementation and the basic properties of its universality class. I present
results from numerical simulations and insist on the role played by symmetries
and conservation laws. Analytical arguments are presented in an accessible and
simplified way, but ample references are given for more advanced readings.
