We are approaching a golden era in gravitational wave (GW) and multimessenger astronomy. The detection and characterisation of a number of GW merger events has naturally triggered widespread debate regarding the possible formation channels and population of such sources in the Universe. In my talk, I shall explore the formation of binary black hole (BBH) mergers via dynamical interactions in moderately massive star clusters, that begin their life as young massive clusters (YMCs) and evolve into moderately massive open clusters (OCs). Based on a suit of state-of-the-art direct N-body evolution of models of such star clusters, I shall compare the BBH mergers from the cluster models to the observed GW event population. I shall also discuss the formation of merging BBHs from evolution of massive binaries in isolation. The results suggest that YMC/OCs of the Universe are highly promising factories of the GW events that we observe.