In this paper, we study all ways of constructing modular compactifications of the moduli space \(\mathcal {M}_{g,n}\) of n-pointed smooth algebraic curves of genus g by allowing markings to collide. We find that for any such compactification, collisions of markings are controlled by a simplicial complex which we call the collision complex. Conversely, we identify modular compactifications of \(\mathcal {M}_{g,n}\) with essentially arbitrary collision complexes, including complexes not associated to any space of weighted pointed stable curves. These moduli spaces classify the modular compactifications of \(\mathcal {M}_{g,n}\) by nodal curves with smooth markings as well as the modular compactifications of \(\mathcal {M}_{1,n}\) with Gorenstein curves and smooth markings. These compactifications generalize previous constructions given by Hassett, Smyth, and Bozlee–Kuo–Neff.
