Leopold Ruzicka (1887-1976), Croatian-born Swiss chemist, in uniform as an air raid lieutenant. Ruzicka studied in Croatia (then part of the Austro-Hungarian Empire) and Germany. He obtained his doctorate in 1910 under German chemist Hermann Staudinger and moved to Switzerland to continue his work with Staudinger. Ruzicka worked on insecticides, perfumes and sex hormones, devising pioneering methods of organic synthesis (including Ruzicka cyclization). His laboratory became a world centre of organic chemistry. He was awarded the Nobel Prize in Chemistry in 1939: 'for his work on polymethylenes and higher terpenes'.