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 Fleck Ludwik Fleck Ludwik Fleck (11 July 1896 – 5 June 1961) was a Polish and Israeli physician and biologist who did important work in epidemic typhus in Lwów, Poland, with Rudolf Weigl and in the 1930s developed the concepts of the ""Denkstil"" ("thought style") and the ""Denkkollektiv"" ("thought collective"). The concept of the "thought collective" defined by him is important in the philosophy of science and in logology (the "science of science"), helping to explain how scientific ideas change over time, much as in Thomas Kuhn's later notion of the "paradigm shift" and in Michel Foucault's concept of the "episteme".