A Canadian gold coin named "Big Maple Leaf" which bears the image of Queen Elizabeth II was stolen in the early hours of Monday morning from Berlin's Bode Museum.
The coin is made out of pure gold, weighs about 100 kilos and has a face value of around $1 million (794,344.27 pounds).
"The coin was stolen last night, it's gone," museum spokesman Markus Farr said.
Given the high purity of the gold used in the coin, its material value is estimated to be $4 million.
The museum said on its website that the coin was issued by the Royal Canadian Mint in 2007 and that it was featured in the Guinness Book of Records for its "unmatched" degree of purity.
The coin, with a diameter of 53 centimetres and 3 centimetres thick, was loaned to the Bode Museum in December 2010.
Police said it was probably stolen by a group of thieves who entered the museum undetected through a window, possibly with the help of a ladder.
we have so far we believe that the thief, maybe thieves, broke open a window in the back of the museum next to the railway tracks," police spokesman Winfrid Wenzel said. "They then managed to enter the building and went to the coin exhibition."The coin was secured with bullet-proof glass inside the building. That much I can say," Wenzel added.
"Neither I nor the Bode Museum can go into detail regarding personnel inside the building, the alarm system or security installations."
The Bode Museum has one of the world's largest coin collections with more than 540,000 items.

Bulmer Art Heist Back-Story:
http://arthostage.blogspot.co.uk/2015/09/stolen-art-watch-bulmer-paintings.html
Followed by:
http://arthostage.blogspot.co.uk/2016/05/stolen-art-watch-bulmer-paintings-dick.html
Cops hunt thieves who stole £2.5million worth of art from Bulmers cider tycoon’s mansion while he was on luxury Barbados holiday
Some of the gang are believed to have fled with the paintings, while others loaded the boot of the Bulmers’ Mercedes with a safe with £1million worth of jewellery inside.
The shocked house sitter was found at their house, The Pavilion near Bruton, Somerset, 18 hours after the break-in.
Cops have arrested 11 men in connection with the aggravated burglary.
All remain on bail pending further investigation.
The latest arrest was a 42-year-old man from Small Heath, Birmingham.
The unnamed man was arrested on suspicion of conspiracy to commit fraud, and conspiracy to handle criminal property.
Renewing their appeal for witnesses eight years on, Avon and Somerset Constabulary said all but one of the 15 paintings taken have been recovered by private investigators.
The outstanding painting is Sir John Lavery’s “After Glow Taplow.”
The jewellery and silverware taken in the heist have great sentimental value to the Bulmer family.
Upon getting one piece of art back in 2015, Mr Bulmer, who was MP for Kidderminster between 1974 and 1983, said he was “thrilled”.
Police are appealing for jewellers and antique and second-hand shop owners who may have been offered the items to come forward.
Anyone able to help should call the Operation Shine investigative team via 101, quoting reference Op Shine 3559609.
Stolen Van Goghs back on display after years in criminal underworld
However, Dutch culture minister Jet Bussemaker said their real value would be in the eyes of those who can now see them again.
Thieves seized the canvases from the Van Gogh Museum in Amsterdam - which contains the world's largest collection of Van Gogh works with more than 200 paintings and 500 drawings - after breaking in through the roof.
One of the men convicted over the theft, Octave Durham, has revealed that he was actually after the artist's better known works, but they were harder to steal.
"The heist took about three minutes and 40 seconds," Durham says in the film, the New York Times reported. "When I was done, the police were there, and I was passing by with my getaway car. Took my ski mask off, window down, and I was looking at them."
He said he and his accomplice had wanted to steal Sunflowers but the artwork was too well guarded, Trouw newspaper reported. They then turned their attention to The Potato Eaters, considered the painter's first masterpiece, but decided it was too big to fit through the hole they had entered through.
Durham told the filmmakers he had selected the seascape because the thick paint convinced him it would be valuable. He was arrested a year later in the Spanish resort of Marbella and convicted in 2005, but had until now maintained he was innocent.
The theft was a case of "art-napping" by an opportunist burglar, art investigator Arthur Brand told the BBC.
"No art collector will pay for stolen art they can't display," he said. But stolen art could be used as leverage by criminals who offer its return in exchange for reduced sentences for their crimes.
Dutch criminal Cor van Hout - who became notorious for kidnapping the beer tycoon Freddy Heineken for an estimated $10m (£8m) ransom in 1983 - wanted to buy them but he was gunned down in a gangland hit before the deal could be done.
Another potential buyer met the same fate and the paintings were eventually sold to Raffaele Imperiale, a low-ranking mafioso who was at the time running an Amsterdam coffee shop.
Imperiale paid about €350,000 ($380,000; £305,000) for the paintings and his lawyers told the New York Times he had bought them because he was "fond of art" and they were a "bargain".
Imperiale was among several suspected dealers arrested by Italian police last January. Another suspected dealer arrested at the same time reportedly told investigators the paintings were at Imperiale's house.
The BBC's James Reynolds in Rome says mafia members are not known for their understated good taste and raids have often revealed a preference for ostentatious, kitsch decoration, so Imperiale was unlikely to have bought the paintings for display purposes.
They were found wrapped in cloth in a safe in a house in the picturesque seaside town of Castellammare di Stabia, near Pompeii, last September.
Van Gogh Museum Director Axel Ruger said it was wonderful to have the works back on display.
"I think it's one of the most joyous days in my career really," he said.
The museum has not made any comment on the upcoming documentary, Trouw said.
Why are the paintings significant?
Vincent Van Gogh (1853-1890) is widely considered the greatest Dutch artist after Rembrandt.Seascape at Scheveningen was one of only two seascapes he painted while he lived in the Netherlands.
It shows a foaming, stormy sea and thundery sky, and was painted in 1882 while he was staying in The Hague.
Congregation Leaving the Reformed Church at Nuenen (1884) was painted for Van Gogh's mother, but also partly for his father, who had become a pastor at the church in 1882. When his father died in 1884, Van Gogh added churchgoers, including a few women wearing shawls used for mourning.
Van Gogh committed suicide in France in 1890.
Recovering stolen masterpieces
The 2002 Van Gogh museum raid was one of a series of thefts that shocked the art world.In 2004, two Edvard Munch masterpieces, The Scream and Madonna, were seized by armed men who raided the Munch museum in Oslo. Several men were jailed and the paintings later recovered after painstaking detective work in 2006.
Another version of The Scream was stolen from the National Art Museum in Oslo in 1994 and that too was later recovered in a sting operation by UK detectives.
In 2012, seven artworks were stolen from Rotterdam's Kunsthal museum, including paintings by Picasso, Monet and Matisse. Two thieves were later jailed, telling a Bucharest court that security at the museum had been lax. Some of the paintings were destroyed in an oven.
Earlier this year, four paintings out of a haul of 24 stolen from a Dutch gallery in 2005 were recovered in Ukraine.
As Stolen Van Goghs Return to View, a Thief Tells All



16 Years Later, Stash of Stolen Paintings Found Near Crime Scene
