Made of platinum and boasting almost 3,000 diamonds, Parisian jeweller Cartier spent almost three years crafting the so-called Patiala Necklace from 1928, a necklace for the then-Maharaja of the Indian state Patiala, Bhupinder Singh of Patiala (pictured). The opulent piece of jewellery, which has been valued at over $30 million (£22.3m) in today's money, also contained a number of Burmese rubies as well as a yellow 428-carat De Beers diamond, the seventh largest in the world.

In 1948, the opulent piece of jewellery mysteriously disappeared from the royal treasury of Patiala. Decades later, in 1982, the De Beers diamond reappeared at auction in Geneva, Switzerland. Another 16 years later, a Cartier representative stumbled upon the platinum chains of the necklace in a second-hand jewellery store in London, but with the biggest diamonds and the rubies gone. While Cartier was able to recreate the necklace, the whereabouts of the original gemstones are still a mystery.

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