More widely observed than any other holiday, Passover celebrates the exodus of the Israelites and redemption after 400 years of Egyptian slavery. It is a week-long major Jewish holiday. During this week, it is tradition to avoid breads made with yeast to recreate the experience of passing over Egypt. Leavened bread was forbidden during the exodus since the Jews were in a hurry to leave. Today, matzo bread, similar to a cracker, is substituted.