Galactic Collisions: The Growth and Merger of Supermassive Black HolesThe discovery of gravitational waves from two merging black holes at cosmological distance motivates the study of the galactic environments hosting coalescing black holes. This detailed study is best carried out in nearby merging galaxies where we have the ability to resolve the nuclear environment in the vicinity of colliding supermassive black holes to within tens of parsecs spatial resolution. In the merger-driven scenario of galaxy evolution, gas-rich galaxy mergers provide a means to funnel gas into the central region of the system, consequently triggering episodes of supermassive black hole growth as well as intense nuclear star formation. The details of the gas fueling and feedback processes that subsequently drive galaxy evolution are often obscured by the cocooning dust stirred up from the violent interaction. Thus, to circumvent the dust obscuration, tracing nuclear gas dynamics in the near-infrared regime presents the most direct way to examine the feeding and feedback events associated with supermassive black holes at small scales, particularly in the centers of interacting galaxies whose collision course leads up to merging black hole coalescence. In this talk, I will present results from our Keck survey that highlights the gas kinematics around black holes in nearby galaxy mergers as they transition from kiloparsec separations to coalescence. Our findings characterized and addressed the nature of nuclear disks, molecular gas outflows as driven by active black holes, as well as the shocked and turbulent gas in the interstellar medium within the progenitor galaxies. The power of high-resolution near-infrared diagnostics in dissecting how systems dynamically evolve throughout the course of galaxy mergers will become indispensable for understanding galaxy evolution as we enter an exciting era of astronomy with the imminence of the James Webb Space Telescope, 30-meter class telescopes, Laser Interferometer Space Antenna, and beyond.