Protein Explorer is free software for visualizing the three-dimensional structures of protein, DNA, and RNA macromolecules, and their interactions and binding of ligands, inhibitors, and drugs. It is arguably the easiest-to-use software of its kind. It is suitable for high school and college students (ages 16 years and older), yet it is also widely used by graduate students and researchers. This site provides instruction in the use of Protein Explorer and simplifies queries of the Protein Data Bank.