Utilizing high-resolution electron microscopy and image simulation, it is demonstrated that some of the crystal lattices of Fe-doped CaCu3Ti4O12 are intrinsically bent at the nanometer scale. A comparison between experimentally obtained and simulated images indicates that the bending angle is of a few milliradians, which is remarkable in a brittle oxide. Despite such lattice distortion, much of the lattice strain induced by the distortion appears to be released at the domain walls where a number of misfit dislocations are present. (c) 2006 American Institute of Physics.