Passover, also called Pesach, is one of the major Jewish holidays. The week-long holiday begins at sundown on the first day. It follows the lunar calendar, meaning it takes place every year on different dates, but it usually falls in mid-March or April. It celebrates the liberation of the Israelites from slavery in ancient Egypt under the leadership of the Old Testament prophet Moses.

According to the Old Testament, God acted through Moses to demand that the Pharoah free the Israelites. After the ruler initially refused, God sent ten destructive plagues to the Egyptians, including the death of every first-born child. The Israelites were spared this loss by marking their doors with a lamb's blood — in this way, they were "passed over."

After the plague of death, Pharoah let the Israelites go, but then changed his mind and chased them down with his army. At the Red Sea, Moses held out his staff, God parted the water, and the Israelites crossed the dry passage before the waters then tumbled down upon the Egyptian army. The scene has inspired many works of film and art, such as this 16th-century work by Lucas Cranach the Elder.

Many of the events in the Passover story are symbolically represented in the Passover dinner meal, or seder. The most important seders take place on the first and second nights of the holiday. The Haggadah (above), a text that recounts the Passover story and lays out special blessings, frames the meal. A seder's length can vary greatly depending on the Haggadah used. Sometimes songs are also sung.

At the center of the table will be the seder plate — with specific and symbolic foods upon it: a shankbone (for the sacrificed lamb); a hard-boiled egg (life and birth); bitter herbs like horseradish (the bitterness of slavery); a sweet paste called charoset (the mortar in the pyramids); and a leafy green like parsley (hope). A bowl of salt water on the table represents the slaves' tears.

Matzo, matza or matzoh: No matter how you spell it, one thing remains constant — there's no leavening agent in the thin cracker that is a key part of the seder. It's said that when the Israelites left Egypt, they left in such haste that there was no time to let the dough rise. Many Jews avoid any leavened foods during all of Passover, though there is great variation in how this is observed.

Ten drops of wine are placed on one's plate for the ten plagues. One is also supposed to drink four cups of wine, representing promises made by God to the Israelites. A glass of wine is also set aside for the prophet Elijah, and many people open their doors to let him in. This gesture is also a symbol of openness — a seder is meant to be an event at which strangers and the needy are welcome.

The meal itself is eaten in the middle of the seder. The foods served can vary greatly depending on what regional culinary traditions they draw from. Whereas Jews from Eastern Europe may have a veal roast, North African Jews may serve a stew similar to a tagine. And Sephardic Jews originating in Spain may make the sweet charoset with dates and dried fruit, abundant in the Mediterranean.