Authorities were racing Monday to reassure the public about security at key cultural sites — and find the jewels stolen from the museum before they can be broken up and melted down.

From the Mona Lisa to the jewels of Napoleon, the Louvre has experienced over a century of high-profile heists.

Masked thieves stole priceless jewels from the Louvre on Sunday morning. The Paris museum has suffered a string of successful art heists, dating back to the theft of the Mona Lisa in 1911.

More than 25 years before Sunday's heist at the iconic museum, a thief took a 19th-century painting in broad daylight.

A crown that once belonged to Empress Eugenie of France was damaged by thieves during Sunday's heist at the Louvre Museum in Paris.

A tiara, sapphire necklace and the right earring from the sapphire set, which were worn by Queen Marie-Amélie and Queen Hortense, were stolen in the heist. The set is rumored to have first belonged to Queen Marie-Antoinette. The set includes 24 sapphires and 1,083 diamonds, according to the Louvre .

The Louvre Museum in Paris remains closed to the public after robbers stole imperial jewels in broad daylight on Sunday.