  The systematic study of planar semimodular lattices started in 2007 with a
series of papers by G. Gr\"atzer and E. Knapp. These lattices have connections
with group theory and geometry. A planar semimodular lattice $L$ is {\it slim}
if $M_3$ it is not a sublattice of $L$. In his 2016 monograph, "The Congruences
of a Finite Lattice, A \emph{Proof-by-Picture Approach}", the second author
asked for a characterization of congruence lattices of slim, planar,
semimodular lattices. In addition to distributivity, both authors have
previously found specific properties of these congruence lattices. In this
paper, we present a new property, the {\it Three-pendant Three-crown Property}.
The proof is based on the first author's papers: 2014 (multifork extensions),
2017 ($\mathcal C_1$-diagrams), and a recent paper (lamps), introducing the
tools we need.
