Mathematicians have discovered a convex polyhedron, called the Noperthedron, that cannot pass through itself, resolving a centuries-old geometric mystery. The Noperthedron has 90 vertices and 152 faces, and its discovery proves that not all convex polyhedra have the Rupert property. The proof required a combination of theoretical advances and massive computer calculations. The finding has implications for the study of convex polyhedra and their properties.