Chongyang Festival，falls on the ninth day of the ninth lunar month, because of which，it is also named as the Double-ninth Festival, which has a history of some 2,000 years. As an important festival in ancient China, Chongyang Festival was celebrated by holding various activities, such as climbing mountains, appreciating chrysanthemums, wearing cornel and eating Chongyang cakes. Climbing mountains is a major custom in Chongyang Festival. Ancient people thought climbing mountains on this day could help them avoid misfortune and prevent disasters. In recent years, a new meaning has been given to the old festival，and it gradually becomes an annual Seniors’ Day, on which various activities are held in honor of senior people.
The 9th day of the 9th lunar month is the traditional Chongyang Festival, or Double Ninth Festival.
It usually falls in October in the Gregorian calendar. In an ancient and mysterious book Yi Jing, or The Book of Changes, number 6 was thought to be of Yin character, meaning feminine or negative, while number 9 was thought to be Yang, meaning masculine or positive.
So the number nine in both month and day create the Double Ninth Festival, or Chongyang Festival. Chong in Chinese means double.
Also, as double ninth was pronounced the same as the word to signify forever, both are Jiu Jiu, the Chinese ancestors considered it an auspicious day worth celebration. That's why ancient Chinese began to celebrate this festival long time ago.