It's the photo of the celebration gathering of NCU Math78 (both computational and pure math majors) for 20th graduation anniversary at Da4 Dong1 San1 Du4 Jia4 Chun1, Jishui County, Jiangxi (October 2-5, 2002). The activity was very successful, exciting and joyful. There were totally 75 old classmates joining the gathering.