By Kristen Johanson

By Kristen Johanson

PHILADELPHIA (CBS) — If you saw people dressed in white headed south on Broad Street, it was for the annual pop-up picnic called Diner En Blanc. Rain or shine, the event goes on.

Participants pack a table, chairs and food, then await the reveal of the secret location of the party.

This year, it was held on the grounds of the Navy Yard.

Dave and Fay left their kids at home for a night out, and say the hardest part was finding something to wear.

“New clothes to buy, because I have no white clothes, but the dinner and the table wear, there’s a little bit of preparation, probably a week’s worth.”

About 4,500 people braved the rain and arrived on Navy Yard grounds for the popular event.

Natanya DiBona is co-host of the event, which takes a year to plan.

“We thought in our fourth year it was time to show off a different part of the city, we had been pretty much in the center of things for a while,” said DiBona.

PHOTOS: Fourth Annual Diner En Blanc

Di Bona says more than 30,000 people try to get in.

“If you’ve gone the year before, you’re automatically invited, and then you can recommend friends in phase two. And then this year we introduced a lottery for phase three.”

Rain can’t dampen the spirits for Mark and his crew.

“Every year, we have more and more friends, we have a nice group. We will probably have about twenty next year, and we’re going to be here every year.”

For Mika and Mark, it’s a little more special this year.

“We got engaged here last year.”

“We are going to be here every year… rain or shine, we are here.”