  It is commonly believed that the transition line separating a liquid and a
solid cannot be interrupted by a critical point. This opinion is based on the
traditional symmetry argument that an isotropic liquid cannot be continuously
transformed into a crystal with a discrete rotational and translational
symmetry. We present here a molecular-dynamics simulation of a simple monatomic
system that demonstrates a liquid-solid spinodal terminating at a critical
point. We show that, in the critical region, the isotropic liquid continuously
transforms into a phase with a mesoscopic order similar to that of the smectic
liquid crystals. We argue that the existence of both the spinodal and the
critical point can be explained by the close structural proximity between the
mesophase and the crystal. This indicates a possibility of finding a similar
thermodynamic behaviour in gelating colloids, liquid crystals and polymers.
