Appears in collection : Algebraic Structures in Perturbative Quantum Field Theory: a conference in honour of Dirk Kreimer's 60th birthday

Amplitudes of one-loop graphs are known to be dilogarithms. What can one say about two-loop graphs? In a surprising number of cases, the motive of the second Symanzik of a two-loop graph involves (indeed, the motive is actually built around) the motive of an elliptic curve, suggesting some relation between the amplitude and elliptic polylogarithms. I will discuss a number of examples. This is joint work with C. Doran, M. Kerr, and P. Vanhove.