Below is the Israel Institute of Culture's description of Passover.

Jewish Passover 

[Israel Institute of Culture] 

http://www.ilculture.or.kr/culture/holiday.php?page=1&mode=view&PGn=6&iKeyNum=7&strSkin=gallery_no&pgCode=&SVALUE=YToyOntzOjg6ImtleWZpZWxkIjtzOjc6InN1YmplY3QiO3M6Mzoia2V5IjtzOjA6IiI7fQ== 

Passover is a springtime festival that begins on the 15th of Nisan. It commemorates the exodus of the Israelites from Egypt in the 13th century BCE, when they were freed from slavery and reclaimed their freedom, and freedom is a dominant theme of the festival. Preparation for Passover begins long before the festival, with a thorough cleaning of the home and business. To honor the Biblical commandment in Exodus 12:15-20, we begin by removing leaven from our homes and businesses. The day immediately preceding the start of Passover is a time of preparation, including the burning of foods that are forbidden during Passover. The first night's seder, called a "seder" in Hebrew, commemorates the specifics of their ancestors' freedom from slavery in Egypt, and the entire family sits down to a meal and reads from the Haggadah, the book that tells the story of the Exodus.

Passover food consists of bitter greens to symbolize the suffering of slavery in Egypt, matzah, an unleavened bread, wine, a shank to represent the Passover lamb, hard-boiled eggs, and a haroset (mud) sauce to evoke the work of bricklaying in the Goshen.Passover is a national holiday that, like Yom Kippur, is observed by secular Jews as well. In addition, non-religious Passover rituals on kibbutzim are celebrated as a springtime rural festival.

What's the oldest holiday in the world? It's definitely the Jewish Passover. It's over 3,500 years old. So what's the biggest Jewish holiday? Passover. Passover is the largest Jewish holiday that commemorates the Exodus of the Israelites from Egypt. Passover begins on the 15th of Nisan in the Jewish calendar and lasts for seven days. The first and last days are called Yom Tov (Good Days), and no work is allowed on these days. This day is a national holiday. The five days in the middle are called "Hol Ha Moed" (The Middle Days), and work is permitted on these days.