PARIS, FRANCE (Reuters) – Thousands of people dressed in white gathered in front of Les Invalides in Paris to celebrate the 30th white-clad “Diner en Blanc” picnic on Sunday (June 3) evening. Guests arrived from Parisian streets carrying tables, chairs and baskets full of fine food and wine. The exclusive, invite-only “Diner en Blanc” – or “Dinner in White” in English – is organised every year with the location remaining a closely guarded secret until the last minute to keep diners and the authorities in the dark. Organisers say whilst they are not officially allowed to organise a dinner, they are allowed to hold an improvised picnic — hence the all-important secrecy. But the event does not look like a makeshift affair, with thousands dressed to impress sitting at tables covered in crisp white tablecloths and crowned with candelabras. Once everyone is ready, guests traditionally swing their white cloth napkins as a sign indicating the start of the dinner. Other codes ask that guests leave the place as clean as they find it. The event is held annually at a different Parisian monument. Previous locations have seen guests eating in front of the Louvre, Notre Dame Cathedral and the Place de la Concorde at the foot of the Champs Elysees. The idea has also proved popular abroad, mostly in North America and Europe. After Paris, the biggest gathering is held in Montreal, Canada.