"In 1999 at the World Conference on Science the organisers decided to hold the World Science Fo-rum every two years in Budapest. In 2001 UNESCO declared 10 November to be “World Science Day”, since when science and scientists have been celebrated on this date. From then on-wards, the dates for the World Science Forum have been fixed to coincide with this date. The forums in Budapest over recent years have dealt with a variety of topics for scientists from all over the world: Knowledge and Society (2003), Knowl-edge, Ethics and Responsibility (2005), Investing in Knowledge: Investing in the Future (2007) and Knowledge and Future (2009). In 2011 the central theme of the World Science Forum is The Chang-ing Landscape of Science (2011). By Act XCIII of 2003 the Hungarian Parliament declared 3 November – the day in 1825, on which István Széchenyi offered 1 year’s income from his estates for the purposes of establishing a Learned Society, thus facilitating the foundation of the Hun-garian Academy of Sciences (HAS) – to be Hun-garian Science Day. The series of events for Hun-garian Science Day in 2011 will be held between 3 and 30 November with programmes throughout the country. Its main patrons are traditionally the president of the HAS and the prime minister. (Source: mta.hu) The main motif of the stamp is the logo of the World Science Forum, which includes the name and place of the event in English “WORLD SCIENCE FORUM BUDAPEST”, with the building of the Hungarian Academy of Sciences hosting the event in the background. The first day cover for the stamp depicts a silhouette of the earth and the special postmark is illustrated by a stylised draw-ing of the building of the Hungarian Academy of Sciences."