In 1900 the young Eduard Penkala arrived in Zagreb, then a town of about 60,000 inhabitants in all. Born of Polish and Czech origins in what is now Slovakia, he soon showed solidarity with his new fellow citizens, due to the political troubles. A chemist by profession, he invented over 80 patents in various fields: from a hot water bottle, a precursor of the vacuum flask and a rotating toothbrush to medicines, detergents, insecticides, a brake system, the first anode battery, a compound for gram...