In anticipation of a moonless starry night later on, playing on the iPod is Et lucevan le stelle from Puccini's Tosca, performed by Carlo Bergonzi.
This particular Tosca, with Maria Callas(Floria Tosca), Tito Gobbi(Scarpia) and Carlo Bergonzi(Mario Cavaradossi) is my favourite (although Bergonzi is not one of my favourite Cavaradossis).
According to Tito Gobbi's memoires, in one of her performances as Tosca, Maria Callas came too near to the candles burning on Scarpia's desk and her wig caught on fire. Gobbi (Scarpia) immediately improvised a raptor-like motion: he jumped on Tosca, embraced her and extinguished the flames. Tosca rejected him with disgust, but then whispered him a "thank you, Tito"... just before killing him.
Tosca's finale seems to be prone to accidents and there are a lot of tales about various mishaps. One of the most popular is the the bouncing Tosca: Tosca as usual jumps from the walls of Castel Sant'Angelo. But the stage workers had improved her security by replacing the mattress with a trampoline and so Tosca appeared 2 or 3 times from behind the wall! The collective suicide is also popular: the stage director was giving last-minute instructions to the extras hired as soldiers. There had been no stage rehearsal, and he gave them the usual instruction "exit with the principals". When Tosca leapt from the parapet, seeing no other principals left on stage, they all dutifully jumped after her, giving a Shakespearean greatness to the final tragedy.
Also memorable is Placido Domingo's headlong fall while rushing down from the scaffolding during Act 1 of "Tosca live at the real times & places": he smashed into the bottom of the fence of the real Cappella Attavanti, giving a definite hint of realism to the broadcast.