Vietnamese Lunar New Year is the most important celebration in Vietnamese culture. It celebrates the arrival of spring based on a lunisolar calendar. It takes place from the first day of the first month of the Vietnamese calendar until at least the third day. Many Vietnamese prepare for Tet by cooking special holiday food and cleaning the house. These foods include chưng cake, dày cake, and sticky rice. Many customs are practiced during Tết, such as visiting a person's house on the first day of the new year, ancestor worship, wishing New Year's greetings, giving lucky money to children and elderly people, and opening a shop. Tet is also an occasion for pilgrims and family reunions. They start forgetting about the troubles of the past year and hope for a better upcoming year. The Vietnamese people do not say bad things during Tet holiday. They also avoid debating to others. When there are any conflicts, keep calm, a happy mind and solve it peacefully. Sweep house in Tet holiday is also considered to sweep all luck and money out of their house. When visiting to the Vietnamese house in Tet, you should avoid throwing trashes onto the floor. Last but not least, avoid wearing black or white clothes. Black and white are mainly used in Vietnamese funeral, thus it is an unlucky sign if you wear these color clothes in Tet holiday.