The GRACE twin satellites, launched 17 March 2002, are making detailed measurements of Earth's gravity field changes and revolutionizing investigations about Earth's water reservoirs over land, ice and oceans, as well as earthquakes and crustal deformations. The two GRACE satellites have completed more than 13 years of continuous measurements! GRACE TELLUS provides user-friendly Level-3 data grids of monthly surface mass changes, with most geophysical corrections applied, to analyze changes in the mass of the Earth's hydrologic, cryospheric, and oceanographic components. We do so by using GRACE Level-2 data, with additional post-processing, alone or in combination with other ancillary data, to generate gridded, geo-located products (monthly and time-averaged) with the most up-to-date corrections.