A Siberian tiger at the “Tiergarten Schoenbrunn” zoo in Vienna, Austria, on 19 April 2016. The “Tiergarten Schoenbrunn” zoo, with an area of 17,000 square meters, is part of the Schoenbrunn Palace Gardens and the UNESCO World Heritage Site Schoenbrunn. The oldest zoo in the world is one of the top tourists attractions, with more than two million visitors yearly. (Photo by Christian Bruna/EPA)
