Esperanto Day celebrates Esperanto, which is the most widely spoken constructed international auxiliary language. The goal was to create an easy-to-learn, politically neutral language that would transcend nationality and foster peace between people with different languages.
Buying an Esperanto book
International Esperanto community
Zamenhof Day, Zamenhofa Tago, Esperanto Literature Day, Zamenhof's Birthday
15 December is the birthday of Esperanto creator L. L. Zamenhof.