In 1939 there was 3.25 million Jews in Poland. It constituted the second largest Jewish community in the world, were some 10% of the Polish population, reaching higher in cities like Warsaw and Lodz. Germany invasion of Poland in September 1939 marked the beginning of World War II. Almost immediately Jews in each community were registered with the Nazi authorities and were forced to wear a badge with Yellow Star. Later they life that they had before was ceased within the ghettos. Jews of different backgrounds, identities and levels of observance were forced together within the confines of small regions of each town and city. Some surrounded by walls others by fences. All of the 1200 ghettos that was created existed under the careful watch of the SS guards. They were used us a labor for German owned businesses. Living in very poor conditions with the lack of food, hygiene or medical care. With a fear the random shootings and tortures.