Attendees marched up Sixth Street on Thursday evening in all manner of crisp white attire. Guys kept it garden-party classic in an array of linen trousers, shorts, and cotton button-ups.

But the ladies went all out — P. Diddy-white-party chic in simple sheaths, tulle princess skirts, and fit-and-flares topped with sparkling illusion lace bodices. Sheer maxi dresses were sliced with deep slits. Hats ranged from churchgoing big-brimmed to party-stopping blusher.

And nearly everyone had the common sense to wear flats.

This pure-as-the-driven-snow crowd was bringing the swanky soiree to Franklin Square, the no-longer-secret location of the world's largest annual all-white party, Dîner en Blanc.

Dîner en Blanc was launched in Paris in 1988; cohosts Natanya Dibona and Kayli Moran brought it to Philadelphia in 2012. There are about 29 Dîners in the States; Philadelphia's drew 5,300 participants, making it the country's largest.

"There is something about making your way to a secret location that is exciting," said Jeanette O'Keefe, of Pine Hill. O'Keefe, who is in her 60s, was Dîner en Blanc-ready in a pair of flowing white trousers. With friends, her daughter, sushi, and frosted vanilla cupcakes in tow, she was excited. She won her tickets through a silent auction.

"I just know this is going to be a great experience," she blushed with a quick step despite all she was schlepping.

Getting to a Dîner en Blanc isn't an easy task. And I couldn't for the life of me understand why people bother. I mean, don't these people have jobs?  Who has time for all this planning? Why would I even consider bringing furniture — in this case a 28- to 32-inch-square table — to someone else's party, after I paid to get in?

Plus, folks must provide their own Pinterest-worthy centerpieces. This year, people went all out, with dazzling white roses, daisies, and lilies sprinkled with generous pops of pink. Most delicately placed the flowers in pretty, minimalist ceramic vases.

Then there's the food.

But to these partygoers, it was all no big deal. Thursday night, the smell of Italian-sauced pasta wafted through the park.  As the twinkling lights of  Franklin Fountain's carousel danced in the background, balloons danced in the wind. The rosé flowed. Cheese platters were everywhere.  And the charcuterie — I just wanted to pluck a piece of pepperoni from so many plates — was downright mouthwatering. Plank salmon. Rare steak. Couscous. Greens. Grilled everything. And it was all drizzled with EVOO.

"We have curry chicken, Caesar salad, shrimp tempura, sushi, jerk salmon, rice and peas, and cabbage," said Teresa Redmond, 40, sounding as though she were describing her menu to a Food Network audience. "With all that's going on, it's nice to be out at a place where everyone is happy. It's the one time of year that everyone in the city is equal. No one cares about race or where you are from. We are all just having a nice time."

Redmond's table was packed with food and friends, including Brenda Stallings, a lawyer who came to Philly's affair from Little Rock. Stallings is an official Dîner en Blanc hopper. She's signed up to go to one in Haiti with 20 friends soon.

"There is nothing like it," Stallings said, all smiles in her goddess maxi.

Brandon Washington, 29, proposed to Natasja van Dijk, 24, on Thursday. (Washington is the son of the late Ron Washington, the man behind South Street's now-closed Ron's Ribs.)

Washington's Dîner en Blanc setup also was a smorgasbord of food and friends.

"Well, my girlfriend and my mom suggested I should do it here," Washington said, still nervous. His eyes, however, sparkled with a "yeah, I just did that" twinkle. As he talked, Van Dijk rubbed her belly. Their baby is due in November.

"It's just so beautiful," Van Dijk said.

After some more small talk, the newly betrothed darted off to take a spin on the carousel.

They'll remember this night for the rest of their lives.

Maybe I finally understand the magic of Dîner en Blanc.