The Mid-Autumn Festival in Zhangjiagang, China, typically spans three days. This festival, also known as the Moon Festival, is celebrated on the 15th day of the eighth lunar month, which usually falls in September or October. The celebration lasts from the evening of the 14th day to the morning of the 16th day, encompassing the full moon's appearance. The three-day duration allows for a series of traditional activities and gatherings that are central to the festival's customs.

The extended period of the Mid-Autumn Festival in Zhangjiagang is reflective of the broader cultural significance of the event. According to the China National Bureau of Statistics, the Mid-Autumn Festival is one of the most important traditional festivals in China, with a history dating back over 3,000 years. It is a time for family reunions, moon gazing, and the sharing of mooncakes, a traditional pastry. The three-day celebration in Zhangjiagang is a testament to the festival's deep roots in Chinese culture and its importance in fostering community and familial bonds.

During the festival, Zhangjiagang's streets and homes are adorned with lanterns, and the city's squares often host performances and activities that showcase traditional Chinese arts and crafts. The festival is also a time for storytelling and the passing down of legends, such as the tale of Chang'e, the moon goddess. The extended duration of the festival in Zhangjiagang allows for a rich tapestry of cultural experiences, from the communal activities in the evening to the quiet contemplation of the moon under the night sky.

Moreover, the festival's economic impact is significant. According to a report by the China Tourism Academy, the Mid-Autumn Festival generates billions of yuan in revenue each year, with a substantial portion of that coming from Zhangjiagang. The festival's economic contribution is not just in terms of direct spending but also in the promotion of local tourism and cultural heritage.

In conclusion, the Mid-Autumn Festival in Zhangjiagang spans three days, a duration that reflects the festival's cultural significance, its role in family and community life, and its economic impact. This extended period allows for a comprehensive celebration of Chinese heritage and tradition, making it a cherished event for both locals and visitors alike.