What catastrophic event provides the necessary extreme conditions for the r-process to forge the heaviest elements beyond iron?

Answer

Core-collapse supernova explosion

The r-process requires a massive, short-lived flood of neutrons, conditions thought to exist only during the violent core-collapse supernova explosion of a massive star or possibly during neutron star mergers.

What catastrophic event provides the necessary extreme conditions for the r-process to forge the heaviest elements beyond iron?
Elementlife cyclestarFusionnucleosynthesis