 Numerous inventors and scientists worked in Munich, including Alois Senefelder, Joseph von Fraunhofer, Justus von Liebig, Georg Ohm, Carl von Linde, Rudolf Diesel, Wilhelm Conrad Röntgen, Emil Kraepelin and Alois Alzheimer, and the young Albert Einstein attended the Luitpold Gymnasium.In 1911 the Hellabrunn Zoo opened in the city.Munich also became a center of the arts and literature again, as Thomas Mann, Henrik Ibsen, Richard Wagner, Richard Strauss and many others prominent figures lived and worked there.