National Museum of Natural History, Smithsonian, Washington, D.C.
The Smithsonian has its own Castle, but the institution's diamonds aren't there—instead, they sit across the Mall in the Natural History Museum. The prize of the exhibit is, of course, the Hope Diamond, the 45.52-carat dark blue stone that the gem's last owner, Harry Winston, donated to the museum in 1958 with the hope of starting a national collection. Although it is nicknamed the "Diamond of Disaster," most of the previous owners of the "cursed" gem did not meet an untimely death.
However, the same cannot be said for the owner of another pair of famous gems at the museum: Marie-Antoinette's earrings comprise two large diamonds weighing in at 14 and 20 carats, along with several other smaller stones. Another Frenchwoman—Marie-Louise, the second wife of Napoleon Bonaparte—once wore an elaborate diamond necklace now on display. It consists of 172 white diamonds weighing a total of 263 carats.
The museum also owns several colored diamonds, including one of the largest diamonds to remain uncut—the 1.5-inch-tall, yellow Oppenheimer Diamond. The DeYoung Red Diamond, though only 5.03 carats, is the largest of that color and had once been mistaken for a garnet. And the 67.89-carat champagne-colored Victoria-Transvaal diamond, which is set into a necklace with more than 100 smaller stones, was worn in the 1952 movie, Tarzan's Savage Fury.
Armoury Chamber, Kremlin, Moscow, Russia
According to one tale, the Orlov diamond was once set as the eye of an idol at a shrine to the Hindu god Vishnu in southern India, but was stolen by a French deserter. Some have theorized that the Orlov may be the Great Mogul diamond from India, stolen by the Persian invader Nadir Shah in 1739.
Whatever its origin, the Orlov is named for Count Grigori Orlov, who bought the diamond in 1775 in Amsterdam and then gave it to Catherine the Great of Russia, his former lover, in an attempt to win back his position as her favorite. He never did, but the empress had his gift placed in the top of the Imperial Sceptre, where it remains today.
The scepter and other jewels—including the Shah, one of the few historic diamonds with an engraved inscription—can be found in the Russian Diamond Fund, on display in the Armoury Chamber in Moscow's Kremlin. The museum building serves as a treasure house for the state, also displaying gold and silverware, weapons, textiles and royal carriages. Elsewhere in the complex, visitors can tour cathedrals and the Patriarch's Palace.
Treasury, Topkapi Palace Museum, Istanbul, Turkey
After the city of Constantinople fell to the Ottomans in 1453, its conqueror, Sultan Mehmed II, renamed the city "Istanbul" and later built the majestic Topkapi Palace. Growing to cover 173 acres, the palace served as the official residence of the Ottoman sultans and a site for government administration for 380 years before it was turned into a museum in the early 20th century.