Here, we present a comprehensive study on the structure of multi-twinned decahedral-based nanorods and nanowires (Dh-NWs), specifically for the case of silver. We have demonstrated that their high-resolution transmission electron images (HRTEM) can be interpreted as a Moire pattern contrast based on a multi-twinned decahedron, and that their selected-area electron diffraction (SAED) patterns can be also completely generated through the same multi-twinned decahedron basis. We propose that the structure of these nanowires can be interpreted as a chain of decahedra joined along the vertex, which is parallel to the five-fold symmetry axis. This chain can be generated through [111] growth for FCC structures. (c) 2005 Elsevier B.V. All rights reserved.