The pervasiveness of GPS-equipped mobile devices has been nurturing an unprecedented amount of semanticsrich spatiotemporal data. The confluence of spatiotemporal and semantic information offers new opportunities for extracting valuable knowledge about people's behaviors, but meanwhile also introduces its unique challenges that render conventional spatiotemporal data mining techniques inadequate. Consequently, mining semantics-rich spatiotemporal data has attracted significant research attention from the data mining community in the past few years. In this tutorial, we start with reviewing classic spatiotemporal data mining tasks and identifying the new opportunities introduced by semantics-rich spatiotemporal data. Subsequently, we provide a comprehensive introduction of existing techniques for mining semantics-rich spatiotemporal data, covering topics including spatiotemporal activity mining, spatiotemporal event discovery, and spatiotemporal mobility modeling. Finally, we discuss about the limitations of existing research and identify several important future directions.