Abstract: Recently, S.Agafonov and E.Ferapontov have introduced a construction that allows to associate naturally to every system of partial differential equations of conservation laws a congruence of lines in an appropriate projective space. In particular to hyperbolic systems of Temple type, there correspond congruences of lines that place in pencils of lines. The language of Algebraic Geometry turns out to be very natural in the study of these systems. In the talk, after recalling the definition and the basic facts on congruences of lines, I will illustrate the Agafonov-Ferapontov construction and some results of classification for the Temple systems.