A regular dodecahedron is a three-dimensional geometric shape composed of twelve congruent regular pentagonal faces. Each face of a regular dodecahedron is identical, meaning all sides are the same length, and all angles between adjacent sides are equal. It's one of the five Platonic solids, which are the only convex regular polyhedra. The regular dodecahedron has 20 vertices and 30 edges. It's a symmetrical and aesthetically pleasing shape often encountered in geometry and mathematics.