The traditional Korean calendar was based on the lunisolar calendar, like the Chinese and other East Asian calendars. Dates are calculated from Korea's meridian, and observances and festivals are rooted in Korean culture. The Gregorian Calendar was officially adopted in 1895, but traditional holidays and age-reckoning are still based on the old calendar. The biggest festival in Korea today is Seollnal (the traditional Korean New Year). Other important festivals include Daeboreum (the first full moon), Dano (spring festival) and Chuseok (harvest festival).