Building on the major scientific advances made by the current generation of cm and metre-wavelength telescopes, phase 1 of the Square Kilometre Array (SKA1) will be the next global radio astronomy observatory. It is currently being designed by engineers and scientists from around the world, including China, with the aim of beginning early science operations in 2020. Along with FAST, SKA1 will conduct key tests of general relativity through surveys and timing of pulsars in our galaxy, and beyond. By sampling wide areas and large volumes, it will answer fundamental questions related to the evolution of atomic Hydrogen in the Universe, from the present day back to the Cosmic Dawn. The detection of radio continuum emission in galaxies as far back as the epoch of reionization will probe the cosmic evolution of obscured star-formation. I will give an overview of some of the extragalactic science drivers for SKA1, along with a description of the planned telescopes and the sites that will host them.