A precious gold coin that's in the Guinness Book of Records for its unsurpassed purity was stolen early Monday from a museum in Germany. The coin, which weighs more than 200 pounds and has a diameter of more than 20 inches, was taken from the Bode Museum in Berlin after 2 a.m. local time. German media reports put the current value of the gold coin at 3.7 million euros, or slightly more than $4 million. Read: Ancient Roman coins found in ruined Japanese castle Nicknamed "the "Big Maple Leaf," the coin was issued by the Royal Canadian Mint in 2007, ahead of Queen Elizabeth II's state visit to Germany. It has a face value of more than $1 million and a purity of 999.99/1000 gold.