Passover, the eight-day festival of freedom celebrating the Exodus from Egypt, is probably the foremost Jewish holiday today. It is also one of the world’s oldest continually observed festivals. No products made from regular flour and no leavened food (more precisely, no fermented foods) can be eaten at Passover. This practice is based on a passage from Exodus 12:15, “For seven days you are to eat bread made without yeast. On the first day remove the yeast from your houses, for whoever eats anything with yeast in it from the first day through the seventh must be cut off from Israel.” Pesach in Hebrew means “passing by” or “passing over”; the holiday was called Passover because God passed over the Jewish houses while slaying the firstborn of Egypt. During most Jewish ceremonial meals throughout the year, two loaves of the sweet, enriched bread known as challah are served, but on Passover three matzahs are placed on the table instead. Matzah, the unleavened and quickly baked bread prepared for Passover, reminds contemporary celebrants that the Jews fleeing Egypt had no time to leaven their bread or to bake it properly.