If you're heading into Philadelphia tonight, you may notice that A TON of people are wearing white.

Why?

Well, tonight is the scheduled night for Diner En Blanc, a tradition that is now in its 8th year in Philadelphia. It's a tradition that started in Paris about 30 years ago, and it now celebrated in 80 cities across the world, according to officials.

What is it?

Well, it's a pop-up dinner party that requires attendees to dress in all white. Guests pre-register on the website, and they're notified of the location for the event just moments before it starts. Guests bring their own food for a mass "chic picnic" in a public space.

Here's some footage from last year's event:

So if you're in the city tonight, this is why you'll see THOUSANDS of people wearing white. We've heard that about 6,000 people RSVP-ed to attend the event.

Hopefully, the weather holds out for everyone attending tonight too. We saw photos from New York City's Diner En Blanc (held this July), and we saw a TON of white umbrellas as some thunderstorms rolled through the city at the time of the event.

Getty Images

At least white umbrellas look stylish, right?