I'm in Berlin for the annual ITB travel fair, and last night had one of those magical moments that sometime happen when we travel, a foruitous experience that can't be planned, only enjoyed. Kismet.

We were a small group of magazine people dining at Grill Royal, one of Berlin's restaurants of the moment, overlooking the Spree River from a quay just below fashionable Friedrichstrasse. The massive restaurant is renowned for its beef— entrecôte from Nebraska, Wagyu from Australia, specialty cuts from Argentina—a decidedly gourmet approach to steak. But the menu is varied, with choucroute (dressed sauerkraut), oysters from the island of Sylt, bouillabaisse, and other regional delicacies.

The restaurant decor is minimalist, with spotlighted artwork on the walls, massive columns, dark-wood banquettes. The real decoration comes from the diners themselves—chic, attractive, some young, others young-ish, all wearing fashions you'd find in the cutting-edge boutiques off Unter den Linden a few blocks away.

That night the restaurant was packed, lively. The noise level threatened at any moment to elevate from robust to boisterous, as if everyone had drunk one more glass of Austrian Pinot Noir than was good for them. Slowly rising, a lone musical voice sliced through the din. It came from a young woman at a table near ours, a vaguely Eurasian beauty sitting with a group that I'd earlier picked out as something artsy from somewhere far off—an acting company from Hungary, say, or a dance troupe from eastern Russia. Not unusual in this cosmopolitan capital.

The singer was quickly joined by one of her companions, an equally as exotic-looking woman with a sound as high and silky as the first. The two voices overlapped, harmonized, sang counterpoint, and gained in volume until I could clearly discern "O Sole Mio," the schmaltzy old Italian chestnut that we've all heard a million times. But there was nothing corny in this rendition. It was soulful, spontaneous, seraphic. It was something I'd never heard before, and I was transported.

The duo ended on a stirring harmonized chord that literally sent a chill up my spine. It was only as they concluded their aria that I realized the entire restaurant had gone silent. Gleaming red hunks of Wagyu sat unmolested on their tines as diners remained motionless. Waiters and busboys had stopped in their tracks to listen. Then, as if on cue, everyone in the Grill Royal broke into applause, stomping and whistling, shouting "Brava! Brava!" Some even rose to their feet in ovation. We all felt part of something special.

Later, the two divas sang again from their table. But this time the melody felt a bit forced, the applause obligatory. I can't even recall now, the morning after, the name of the song. The enchanted moment had arrived and left, not to be recaptured. Berlin had gone from being magical to, as ever, merely amazing.

Mark Orwoll is Travel + Leisure’s international editor.