Lawrence Guth teaches lecture 8 of MIT's 18.156 Projection Theory, proving the Szemeredi-Trotter theorem, which gives the sharp bound on the number of incidences between points and lines in the plane. Guth frames the result as the answer to a natural discrete projection problem, then presents a proof built on topology rather than the combinatorial or algebraic methods used in earlier lectures in the course. The eighty minute session works through the topological machinery in detail, contrasting this approach with the techniques students have already seen for related incidence and projection problems. It is a graduate level treatment assuming familiarity with the course's earlier material on projections and discrete geometry, delivered as a standard blackboard lecture with MIT OpenCourseWare production.