  We construct a compactification M_d of the moduli space of plane curves of
degree d. We regard a plane curve C as a surface-divisor pair (P^2,C) and
define M_d as a moduli space of pairs (X,D) where X is a degeneration of the
plane. We show that, if d is not divisible by 3, the stack M_d is smooth and
the degenerate surfaces X can be described explicitly.
