Tết Nguyên Đán, commonly known as the Lunar New Year, is the most important celebration in Vietnam. It marks the arrival of spring based on the lunar calendar, usually falling between late January and mid-February. Families honor their ancestors, clean their homes, and prepare special foods to welcome the new year. During Tết, people often visit relatives and friends, exchange gifts, and give li xi (lucky money) to children. Traditional customs include making bánh chưng (square sticky rice cakes) and setting up altars with offerings. The festival is a time for renewal, reflection, and hope for prosperity in the coming year.