L. L. Zamenhof his honour. In 1959, Unesco honoured Zamenhof in the occasion of his centenary. In 2015 Unesco decided to support the celebration of the 100th anniversary of the death of Ludwik Zamenhof. Zamenhof was 12 times nominated for the Nobel Peace Prize. His birthday, 15 December, is celebrated annually as Zamenhof Day by users of Esperanto. On 15 December 2009, Esperanto's green-starred flag flew on the Google search web page, in a commemorative Google Doodle to mark Zamenhof's 150th birthday. The house of the Zamenhof family, dedicated to Ludwik Zamenhof, and the Białystok Esperanto Centre, are sites of the Jewish Heritage
Ludwik Birkenmajer of scholars. He was married Zofia (Sophie), the daughter of Franciszek Karliński, the professor of astronomy in the Jagiellonian University, and inherited his library embracing mostly the books on mathematics and physics. They had three sons: Aleksander Ludwik (historian of culture and exact sciences, and bibliologist), Józef (poet, interpreter and literature historian), and Wincenty (Polish philologist, teacher and renown Tatra Mountains-climber). His grandson is Krzysztof Birkenmajer (professor of geology, member of the Polish Academy of Sciences). In 2011 the Institute for the History of Science of the Polish Academy of Sciences received the name of father and son: Ludwik &