|Abstract:||Acquired immunodeficiency syndrome (AIDS), caused by human immunodeficiency virus (HIV), accounts for over a million deaths every year. Being in the same family of retrovirus as HIV, Rous sarcoma virus (RSV) causes cancer in chicken. It is known that the structures of RSV and HIV proteins are highly similar, but what is with the structure that makes these viruses such a potent killer? This fundamental question can only be answered when the viruses are magnified to the highest resolution, i.e. seeing every single atom. My research aims to construct the atomic structures of RSV and HIV in their immature stages and identify the key viral components such that the development of the viruses can be interrupted at its infancy. My image illustrates a sense of spatial scale involved in the structure of RSV. It emphasizes the details of the molecular interactions in the angstrom-scale that are essential in the maintaining the multimillion-atom virus structure, spanning a spatial scale as large as 4 orders of magnitude.