Weyl semi-metals are an exciting new class of 3D materials with exotic transport properties. They are characterised by point like singularities in the Brillouin zone at which conduction and valence bands touch. Around these points the electronic quasi-particle excitations can be described by either left- or right-handed Weyl spinors. This makes high energy physics to be the low energy electronics of these materials. Holographic models might be useful in two ways: first some Weyl semi-metals might be strongly interacting and second holography is our best tool to understand and discover new exotic transport properties related to the chiral nature of the charge carriers, especially to chiral anomalies. I will review the construction of a holographic model supporting a topological quantum phase transition between a topological Weyl semi-metal phase and a trivial phase and use it to predict the existence of a new dissipation less form of viscosity (Hall viscosity) in the quantum critical region.