Roving masses of people wearing white, and carrying all necessary picnic accoutrements, descended on lower Manhattan for New York City's fourth Diner en Blanc. Surprised pedestrians watched in amazement as a wave of thousands filed into Nelson A. Rockefeller Park in Battery Park City to set up their feasts along the Hudson River.

The pop-up dinner, which requires attendees to follow a strict white dress-and-decoration code, only reveals its location moments before the event, which adds enough spontaneity to outweigh the rigorous preparation many people undergo. Besides registering months in advance, many of the over 4,000 attendees go the distance creatively, finding amazing clothes, headdresses (we couldn't count the beautiful hats, wraps and fascinators), and table decorations to make the night even more memorable.

One man, Derek who lives in Union Square, brought a PVC arbor, which had inverted parasols filled with lights. "I got it from Pinterest," he confessed—he had enlisted his friends to help build it. He spent the past two days prepping the menu, which included his aunt's "no-fry crispy baked chicken" and a vichyssoise with a "chilled silken puree of chive and cucumber." A woman at the neighboring table muttered, "We picked the wrong table to sit next to." (Derek attended the Diner en Blanc at Lincoln Center and is planning on next year, too—he's probably checking Pinterest now for new ideas.)

Paolo Mathe said that when she knew she was coming, she turned to her "fairy skirt mother," Arlinda McKintosh... but made her own head wrap. McKintosh, who also wore a sparkly beaded mask, explained why she designed big skirts for them, "We have big personalities."

While the grassy park wasn't surrounded by skyscrapers, it afforded views of the Empire State Building to the north, 1 World Trade Center to the east, and Statue of Liberty to the south. Not to mention a gorgeous setting sun—a perfect prelude for dining, dancing and mingling.

Emilie Parylak, a group leader who made a stunning floral hat that lit up, has been going since the first NYC Diner En Blanc in 2011 at the nearby World Financial Center. She explained she loved the "element of joining" and also how people are able to be very individual within the all-white constraints. Another attendee, Gustavo, summed it up, "It's the best of New York."

So, next year, Brooklyn perhaps?