The Jewish New Year is called Rosh Hashanah. It is celebrated on the 1st and 2nd days of the Hebrew month "Tishrei", and in fact begins on the 29th (and last) night of the month of "Elul". This is the only Jewish holiday that lasts for two entire days. The reason behind this celebration is to emphasize the importance of those days.
Judaism is the oldest of the Abrahamic religions, and one of the oldest monotheistic religions in the world, it is 3000 years old. Judaism is associated with the Jewish people, since the religion is not a missionary faith, meaning that it is not open to people of non-Jewish origins. Today, the Jewish population is approximately 14.5-17.4 million.