By Andrew Kramer

PHILADELPHIA (CBS) – A sea of white flooded a historic site Philadelphia Thursday night for the annual Dîner en Blanc, where guests don’t find out where they’re dining until moments before they arrive.

The carousel was spinning and the fountain was shining bright at Franklin Square in Center City, this year’s secret location.

“We love it,” says guest Bonnie Grant. “It’s a sea of happy people dining in white. We have new friends we’ve met here. It’s really great.”

This was Bonnie’s first Dîner en Blanc she got to attend. Same goes for Christina Torres, who calls the location “ideal.”

Gallery: Dîner en Blanc 2017 Philadelphia

“Convenient enough for everyone to get to,” she says. “Secluded enough to still feel private.”

At her table….

“The veterans next to us have a fine spread of cheese, chicken salad, some hot pepper jelly. Over here we have some pre-made wraps and pepperoni and crackers, because we’re newbies.”

Sitting right across from her was Brian Lafferty, decked out in an all-white suit and tie.

“Everyone’s in a positive mood,” he says, “everyone’s just out here to have a nice evening, enjoy each others company and I think everyone’s just happy to be together.”

The night was a little extra special, though, for Brandon Washington and Natasja Vandijk.

“I just asked the love of my life to marry me,” he says.

“I said yes,” she added.

The couple’s first big date was at Dîner en Blanc in Philadelphia several years ago, and they’ve gone back together every year since.

“It’s such a magical occasion,” says Brandon.

This year’s Philadelphia Dîner en Blanc had 5,300 seated guests, making it the largest Dîner en Blanc, organizers say, ever, throughout the country.