On 2020 September 2, the LIGO Virgo collaboration has published the discovery of GW190521, the most massive binary black hole merger observed with gravitational waves to date.  This event opens new perspectives on the study of intermediate-mass black holes and pair instability supernovae. Read more on this extraordinary system here and here. Michela Mapelli has contributed to this extraordinary result as editorial team member. Watch the webinar on GW190521 here.