Discovery of the M87 galaxy John Michell first imagined "black holes" Einstein submits his papers on the General Theory of Relativity Karl Schwarzschild solves Einstein's equations Eddington Expedition First accurate measurement of gravitational redshift First developments of very long baseline interferometry (VLBI) Shapiro time delay Dense mass at the center of the Milky Way is calculated Gravity Probe A confirms gravitational time dilation First successful mm-VLBI observations Dense mass at the center of M87 galaxy is theorized 1.3 mm VLBI observations between IRAM telescopes Existence of black holes is confirmed Viewing the shadow of the black hole at the galactic center, by Falcke et al. VLBI observations at 147 GHz Creation of the Event Horizon Telescope (EHT) Gravity Probe B confirms frame dragging Discovery of event horizon scale structure within M87 First Very Long Baseline Observations performed by ALMA LIGO first detects gravitational waves The telescope first aims at M87 galaxy center Katie Bouman's TED Talk VLTI/Gravity provides first observation of material orbiting close to the point of no return The first image of a black hole is presented to the public Katie Bouman's talk at Caltech