After five years of operation, the GRAVITY instrument has enabled a major step forward in infrared interferometry by its high spatial resolution and sensitivity. This talk will provide an overview of GRAVITY's technology and observation capabilities. I will highlight some revolutionary science results of the Galactic Center, exoplanet, and active galactic nuclei (AGNs). A particular focus will be on AGN broad-line region (BLR) science. The few micro-arcsecond differential spectro-astrometry resolution of GRAVITY provides critical constraints on BLR dynamics and the supermassive black hole (SMBH) mass. Combining GRAVITY with reverberation mapping observations, we aim to investigate the diversity of the BLR dynamics, including Keplerian, inflow, and outflow motion, as well as to discover SMBH binaries. I will end the presentation with an outlook on future GRAVITY+ observations of low and high redshift quasars and the synergies with surveys of the Chinese Space Station Telescope.