The first observing run (O1) of the Advanced LIGO detectors, from September 12, 2015, to January 19, 2016, detected two binary black hole (BBH) mergers, GW150914 and GW151226, with significance greater than 5σ. A third candidate event, LVT151012, was observed with a significance of ~2σ. These detections provide unprecedented insights into the dynamics of compact-object binaries in the high-velocity, highly nonlinear regime. The results confirm that general relativity holds in the strong-field regime of binary coalescence. The observed BBH merger rates are estimated to be between 9–240 Gpc⁻³ yr⁻¹, indicating a significant population of stellar-mass black hole mergers. The results also suggest that future observing runs of the Advanced LIGO and Virgo detectors will yield many more gravitational-wave detections. The analysis used matched-filtering techniques with waveform models based on general relativity, including post-Newtonian theory, the effective-one-body (EOB) formalism, and numerical relativity simulations. The results are consistent between two independent analyses, PyCBC and GstLAL. The parameters of the detected events, including component masses, spins, and distances, are consistent with BBH mergers. The significance of the events is supported by detailed parameter estimation and tests of general relativity. The results provide important constraints on the population of BBH mergers and inform astrophysical predictions of binary black hole formation rates. The findings highlight the potential of gravitational-wave astronomy to probe the universe's most extreme environments.The first observing run (O1) of the Advanced LIGO detectors, from September 12, 2015, to January 19, 2016, detected two binary black hole (BBH) mergers, GW150914 and GW151226, with significance greater than 5σ. A third candidate event, LVT151012, was observed with a significance of ~2σ. These detections provide unprecedented insights into the dynamics of compact-object binaries in the high-velocity, highly nonlinear regime. The results confirm that general relativity holds in the strong-field regime of binary coalescence. The observed BBH merger rates are estimated to be between 9–240 Gpc⁻³ yr⁻¹, indicating a significant population of stellar-mass black hole mergers. The results also suggest that future observing runs of the Advanced LIGO and Virgo detectors will yield many more gravitational-wave detections. The analysis used matched-filtering techniques with waveform models based on general relativity, including post-Newtonian theory, the effective-one-body (EOB) formalism, and numerical relativity simulations. The results are consistent between two independent analyses, PyCBC and GstLAL. The parameters of the detected events, including component masses, spins, and distances, are consistent with BBH mergers. The significance of the events is supported by detailed parameter estimation and tests of general relativity. The results provide important constraints on the population of BBH mergers and inform astrophysical predictions of binary black hole formation rates. The findings highlight the potential of gravitational-wave astronomy to probe the universe's most extreme environments.