(NEWSER) – The old saying about the streets of London being paved with gold is kind of accurate. You just need to go a bit lower. Beneath Threadneedle Street in the city’s financial quarter is a 300,000-square-foot “maze” of Bank of England vaults that hold $200 billion in gold owned by the UK, 30 other countries, and some 25 banks, the BBC reports. In all, about 6,000 tons of gold are held in London vaults—about 20% of all the gold held by the world’s governments—with the vast majority of it sitting on numbered shelves in the subterranean Bank of England vaults. The appearance of the gold bars in the vaults differs based on where they were minted, but each one weighs in at 400 troy ounces and is worth, at the moment, about $500,000. Gold is seen as a safe investment, per the Independent, and investors often move toward the precious metal when other investments are volatile.
“Not quite like storing cash under the mattress,” the BBC says, “but still a way to hedge against risk in other markets.” One historical nugget of note: During WWII, the vaults served as bomb shelters. By that time, though, the gold they held had been secretly shipped to Canada, in case the Nazis overran London. “It’s all very James Bond,” says the Sun of the relatively old-school security still in effect—access involves 3-foot-long keys. “You can’t visit the gold, of course,” observes a post at Atlas Obscura. “But if you want to get close, stand in front of the Bank of England on Threadneedle Street in downtown London, look down, and imagine.” (Apple’s recycling program has netted $43 million in gold.