| This will be an introductory talk to special algebraic cycles on Shimura varieties and their relation to L-functions. No prior knowledge Shimura varieties will be assumed. Chen-Ying Chiou, born in 1911, was a famous scholar and educator in China. Chen-Ying Chiou Fund was established by Prof. Shing-Tung Yau in Morningside Center of Mathematics to support academic lectures and research of distinguished mathematicians and scientists in world-class level. This is an online lecture through Zoom and Tencent Meeting. Zoom (recommend): ID：392 232 6206 Password：200611 Tencent Meeting (can’t ask questions): ID：374 712 584 Password：200611 | 
