Abstract: Observational studies of black holes have progressed by leaps and bounds over the last two decades, advanced by a wealth of new instruments and analysis techniques. I will discuss the unique variability of Sagittarius A* (Sgr A*), the Milky Way’s supermassive black hole, alongside other time domain phenomena in the Galactic Center, traced out over more than 20 years of observations from coordinated multi-wavelength campaigns. I will compare these detailed studies of Sgr A* to equally impressive multi-wavelength observations of M87*. I will also briefly explore how we can continue to push the frontiers of black hole research with existing and next-generation observatories.