Crown Jewels
During the French Revolution, from 11 through 17 September 1792, the Crown Jewels were stolen from Paris! They represented a collection of over 10,000 precious stones (diamonds, pearls, emeralds, saphires, etc.) for a value of 23 millions French Pounds of that time, in other words, a ton of money!
Two of the most precious diamonds were the "Regent" and the "Sancy". They were both later recovered and are now exposed in the Louvre. The third most precious stone was known as the "Bleu de France" (French Blue) and never found its way back to France.
The stone reappeared some twenty years later in London and was sold to a British banker, Thomas Hope, thus becoming known as the "Hope Diamond". After changing hands several times, it was donated to the Smithsonian Institute in Washington D.C. and that's where you can get of glimpse of it now!