Aquaria is a repository for x-ray crystallographic, and nuclear magnetic resonance (NMR) data of large biological molecules and complexes. This resource can be used to find visual representations of a biological molecule of interest. All available structures for a given protein can be viewed at a glance to assist in choosing the most appropriate structure(s) for a given visualization. Once a structure is chosen, users can be directed to the PDB to download coordinate data that can be used with a compatible molecular viewing and manipulation software.