What are the Crown Jewels and what happened to them during the Second World War?

Since the 1600s, the Crown Jewels have been kept at the Tower of London. Often said to be priceless, the Crown Jewels are, at best estimate, probably worth more than £20 billion.

Nearly three million people flock to the Tower of London every year to see them. Today the hundreds of pieces that make up the collection rest on French velvet, in cases made of 5cm-thick shatterproof glass. Visitors must pass through vault doors that, it’s said, can withstand a nuclear explosion.

• Thomas Blood steals the crown jewels

The Crown Jewels are working regalia, and are regularly used by the royals for national ceremonies. The Imperial State Crown, for example, is usually worn by the monarch for the State Opening of Parliament.

Where were the Crown Jewels kept during World War II?

Jonny Wilkes reveals the fate of the Crown Jewels when the Nazis threatened Britain...

Anyone who has been to the Tower of London knows just how heavily and diligently the British Crown Jewels are guarded, which makes their treatment during the war seem rather outlandish. The gemstones were prised from the crowns and sceptres and placed in a biscuit tin. This was then hidden in a hole dug beneath a sally port at Windsor Castle.

Amidst the fear of invasion, George VI had given the order to prevent them falling into Nazi hands. And where else would be safer for the Black Prince’s Ruby and St Edward’s Sapphire from the Imperial State Crown, the Cullinan Diamonds and the infamous Koh-i-Noor than the same palace that his daughters, the young princesses Elizabeth and Margaret, were taken for their own safety?

This content first appeared in BBC History Magazine and BBC History Revealed