A gravitational wave signal named GW190521, detected on May 21, 2019, was caused by the collision of two black holes. These black holes had masses 66 and 85 times that of the Sun, merging to form a final black hole with a mass of 142 solar masses. This event was recorded by the LIGO-Virgo collaboration, a network of observatories designed to detect ripples in spacetime caused by violent cosmic events. The signal lasted only a fraction of a second, which initially made scientists question its authenticity, but further analysis confirmed it as a real astronomical event. The black hole with a mass of 85 solar masses falls within a range known as the pair instability interval (65-120 solar masses). According to current theories, stars in this range should not collapse into black holes but instead undergo a powerful explosion that prevents the formation of a compact object. The discovery of such a black hole challenges existing models of stellar evolution and raises questions about how these massive objects form. The final black hole, with a mass of 142 solar masses, is classified as an intermediate mass black hole. These objects are much more massive than typical stellar black holes but far less massive than the supermassive black holes found at the centers of galaxies. Until this discovery, intermediate mass black holes had only been observed using electromagnetic methods, such as light or radio waves. The detection of one through gravitational waves marks a significant milestone in astrophysics, filling a gap in our understanding of black hole populations. This finding, published in the journals Physical Review Letters and Astrophysical Journal Letters, has sparked new interest in the processes that lead to the formation of black holes in mass ranges previously thought to be impossible. Scientists are now exploring various hypotheses, including the possibility that the 85 solar mass black hole formed from the merger of smaller black holes or that it originated from primordial black holes—objects that may have formed in the early universe. The discovery highlights the need for further research into the origins of these mysterious cosmic entities.