This is a beautiful sheet of 4 stamps, issued by St. Thomas & Principe in 2009, commemorating the Year of Science 2009. Featured on the stamps are the Serengeti National Park, Imperial Zebra, French volcanologist & geologist Haroun Tazieff, Russian chemist & inventor Dmitri Mendeleev, the Red Cross, and theologian & physician Albert Schweitzer. Celebrated calendar months include September with Biodiversity & Conservation, October with Geosciences & Planet Earth, November with Chemistry, and December with Science & Health. The sheet is Scott catalog #2100, and is Post Office fresh, mint never hinged, and F/VF.