 The Lindemann-born criterion states that melting occurs when the energy released from the formation of dislocations exceeds the energy required to form them. However, this does not explain why melting occurs at specific locations within a crystal. Recent studies using atomic column resolution imaging have shown that melting can occur at two-dimensional faults inside crystals below their melting temperatures. This suggests that lattice defects are responsible for the initiation of melting, which has previously been overlooked. This article was authored by Haesam Kim, Ji Sang-an, Young Bin B.A.E., and others.