Chinese New Year, also known as Lunar New Year or Spring Festival, is the most important Chinese holiday. It is defined as the first day of the first month in the traditional Chinese calendar. Unlike the New Year observed by those that use the Gregorian Calendar, which is based on a solar calendar, the Chinese New Year is based on a traditional Chinese lunisolar calendar whose dates indicate both the phase of the moon as well as the time of the solar year. In addition, a lunar month is around two days shorter than a solar month. As such, in order to "catch up" with the solar calendar, an extra month is inserted every few years. This is why, according to the solar calendar, the Chinese New Year falls on a different date each year.
Typically, the celebration begins on the New Year's Eve and lasts for around 15 days through the middle of the first month. Before the celebration, people traditionally clean their houses thoroughly, and also display traditional New Year's decorations. This festivity is a time for family reunion, and is considered the most important part of the Chinese New Year celebration. People often visit relatives and friends, do some shopping, watch traditional Chinese New Year events, launch fireworks, and plan for the coming year. The celebration is sometimes accentuated with a religious ceremony given in honor of heaven, earth, the family's ancestors and other gods. In modern China, Chinese New Year is a celebrated public holiday, and working professionals usually enjoy 7 days of time off, including the weekend. After the family reunion and observation of certain traditions, some modern Chinese families may make use of the public holiday as an opportunity to visit tourist destinations.