But just before I cross the threshold, I feel an electric surge pass through the crowd. As one, we look up and draw breath. Wide-eyed angels tiptoe across golden bubble domes, in millions of tiny, glittering mosaic tiles.

The brain trust of Mediterranean artisans who built San Marco got it exactly right. San Marco was purpose-built as a transcendent collective experience, to overawe throngs of visitors with the shining glory of Venice. After 800 years, that gambit is still working. Yet every guidebook (including some I wrote) advises you when to arrive at San Marco to have the place to yourself, or at least avoid the crowds. We assume the joy of discovery is private, that it can't possibly be crowd-sourced. We are wrong.

Rolling Deep with Strangers

Picture your dream vacation, and it's probably not a crowded church. Try this instead: candy-striped beach-chairs perch on white sand, facing a vast turquoise void.  In an office meeting or a rush-hour commute, that desert island seems like the perfect escape – no wonder it’s the default travel magazine cover shot. But according to research reported in the New York Times, there's one catch to those relaxing dream holidays: they don't actually leave us any happier afterwards. In single-minded pursuit of peace and quiet, we miss out on noisy, disruptive joy.

Peak moments don't require pristine beaches. They can emerge from cramped, deplorable conditions; just think of your favorite concert. I know mine. I camped in ankle-deep mud for three days at the UK's Glastonbury Festival with Finnish and Japanese tentmates, and by the time the headliners played, we had run out of soap, common language and food other than dried octopus. After enduring mediocre opening bands to stake out a spot, our view was suddenly eclipsed by tall late-comers.

San Marco was purpose-built as a transcendent collective experience, to overawe throngs of visitors with the shining glory of Venice. After 800 years, that gambit is still working.

Then, an oooooooOOOOOOOH! rippled through the crowd. A bass line thumped; a thousand craning necks relaxed into a groove. A stranger lifted me so I could see the stage. In my mouth, the octopus jerky turned from salty to sweet. We became mighty, a tide of exultation rolling over the damp, British countryside. Within hours, we would retreat to our separate shores - but at that moment, we were rolling deep with strangers.

Blanket Truths & Mosh Pit Mathematics

Joy induced by crowds can endure not just for days, but for decades. Sociologist Rebecca G. Adams spent a decade studying the crowds at Grateful Dead shows, and found that bonds formed during four-hour concerts ran surprisingly deep, remaining strong over time and across great distances.

For sociologists, this was shocking news: how could strangers' instant connections compare to family ties? But anyone who's been to a great show can pinpoint the moment that connection becomes possible: when you stop caring whose muddy feet are standing on your blanket, offer random pinkish strangers sunscreen and join the euphoric roar of the crowd.

In crowds, humans prove ourselves more adaptable than other territorial animals. Our defensive herding instincts quickly give way, and we become a flock that moves in loose, mesmerizing patterns, like starlings. Cornell physicists compare death-metal mosh pits to molecules in a gas: those in motion continue to move, while stationary ones vibrate. From chaos, dynamic equilibrium emerges .

Never mind that some of the Dead are technically dead, or that even hardcore fans can't understand death metal lyrics. The crowd takes on a life of its own.

Parade Power to the People

When stagecraft is at its most effective, headlining acts become secondary to the euphoria of the crowd. San Francisco's annual Pride Parade is a huge production, with 1.2 million participants, 200 rainbow-festooned floats created through months of volunteer labor and drag costumes entire lifetimes in the making. The sheer effort is spectacular, but the highlight of the parade is always the same: when the people on the sidelines become the main event.

Bystanders break ranks to hug paraders. A grandmother crossing the rainbow-flagged parade route pauses to boogie with a marching band. People shout "You're beautiful!" past the point of hoarseness for strangers who are showing off or just being themselves - granting us all permission to do the same.

Alone, no matter how fabulous, not one of us can be a parade. But with a crowd, we become an event, a sensation, a movement. Joy can elude travel-brochure logic, endure Porta Potties, conquer our fight-or-flight instinct and stop traffic. But sometimes, it needs company to truly flourish.