What do we learn about dense nuclear matter from heavy-ion collision experiments?

Nucleus-nucleus collisions provide the unique opportunity to create and to investigate dense nuclear matter in the laboratory. The collision experiments address fundamental aspects of strong-interaction physics: the nuclear equation of state at high baryon densities and the modification of hadron properties in the dense nuclear medium. The experimental results are relevant for our understanding of the dynamics of core-collapse supernovas, and of the structure of neutron stars. In particular, strange particles are promising diagnostic probes of dense nuclear matter. Existing experimental data, their theoretical interpretations and future experiments will be discussed.