Because they are riddled with defects, bulk crystalline materials never achieve their ideal strength; nanocrystals, on the other hand, are so small there's no room for defects. Yet while nanocrystalline materials may approach ideal strength in their resistance to stress, most nanostructures have shown only a limited ability to withstand large internal strains before they fail. Overcoming this limitation could lead to great advances in engineered materials on all scales.