Ludwik Zamenhof died in Warsaw on 14 April, 1917. History proved his beautiful but idealistic hopes wrong founded. Zamenhof and his wife Klara had three children: Adam, Zofia and Lidia. The youngest Lidia particularly dedicated to promoting the Humanitarian legacy of her father. She was an Esperanto teacher and one of the earliest proponents of the Bahá'í Faith (a monotheistic religion dating back to 19th-century Persian teacher Bahá'u'lláh and emphasizing the unity of all humankind) in Poland.
In December 1938 she had to leave the United States, where she was teaching Esperanto, because the extension for her tourist visa was declined (the reason was her allegedly illegal "paid labour" of teaching Esperanto). In Poland she continued to teach Esperanto and Bahá'í. Soon after the outbreak of WWII, she found herself in the Warsaw Ghetto. As a Jew and proponent of Esperanto, which Adolf Hitler considered an instrument of an international Jewish conspiracy, her fate was doomed. Lidia Zamenhof, just as her sister Zofia, was murdered in Treblinka in 1942. Their brother Adam was murdered in the mass executions in Palmiry forest in 1940.
9. Esperanto is spoken by 2 million people
Although Esperanto hasn't lived up to the idealist expectations of its creator, it remains the most popular constructed language in history. Today, with an estimated number of 2 million users, Esperanto is also the biggest international auxiliary language in the world. In 1999 the number of native speakers was estimated as 2 thousand. Esperanto has also large literature of over 25,000 books, including both original works and translations (among them translations of the Bible, Shakespeare, E. A. Poe, and Adam Mickiewicz).