Learn about the history of summer vacation
A large collection of informational and educational videos from animals and landmarks to language arts and history.
A vast compendium of statistics and up-to-date facts and figures, on everything you need to know.
An unabridged dictionary from aalii to zymurgy, including a pronunciation guide.
An atlas featuring maps and detailed profiles of all 193 countries and the 50 U.S. states.
A current and comprehensive encyclopedia covering all the major branches of knowledge from astrophysics to Zimbabwe.