"Three Tenors - from Caracalla to the World“ is a musical concert event documentary. In addition to detailed musical excerpts, the protagonists tell of the greatest story in classical history. Classical music manager Mario Dradi reports that initially no one believed in his idea of the “3 Tenors.” Conductor Zubin Metha explains the tension between the three singers and his role as tamer of the "band“. DECCA manager Didier de Cottignies explains why the singers made a deal that was unfavorable to them when they first appeared and how he invented “a monster” with this concert event.

Hollywood composer Lalo Shifrin tells how he invented the successful medleys of "O sole mio“ and "New York, New York“ in a Parisian café. Journalist Norman Leberecht defends his criticism of the concert, but acknowledges its paramount importance and legendary director Brian Large gives insights into the biggest media event in classical music.