Passover, also called Pesach, is a major Jewish holiday that celebrates the exodus of the Israelites from slavery in Egypt, which occurs on the 15th day of the Hebrew month of Nisan, the first month of Aviv, or spring. The main ritual of Passover is the seder, which occurs on the first two nights (in Israel just the first night) of the holiday — a festive meal that involves the retelling of the Exodus through stories and song and the consumption of ritual foods, including matzah and maror (bitter herbs).