
Fort Knox is in Kentucky and is one of the most secure places on Earth. It holds most of the U.S. gold reserves, yet few people have ever glimpsed at what else is inside. Only one U.S. president has ever gone into the vault, which has led it to be a source of conspiracy theories and speculation.
The Gold Nobody Sees

The United States government lists Fort Knox as holding 147.3 million ounces of gold, but the public has never seen proof. Audits are seldom conducted, and the most recent official audit was completed in 1953. This has caused many to speculate whether the vault does hold as much gold as stated or if something else is being kept in the vault.
Franklin D. Roosevelt: The Lone Visitor

Fort Knox is of immense value, yet only a single U.S. president has stepped inside: Franklin D. Roosevelt. He did so in 1943, shortly after the vault was built. No president has gone inside since then, adding to the mystery and secrecy of the location.
A Security System That’s Meant to Impress (and Deter)

Fort Knox isn’t just a safe: it’s a military facility. The perimeter is guarded by electric fences, land mines, armed sentries, and four machine-gun turrets. Invisible cameras and motion sensors monitor each section, making it nearly impossible to enter uninvited.
A Door That Will Not Open

The Fort Knox vault door is, as reputation has it, impressive. The enormous 22-ton door is 21 inches thick and built to resist any type of attack, including explosives and blowtorches. No one person is aware of the entire combination, so it’s highly secure.
Theories Run Wild

With hardly any information available to the public, Fort Knox speculation is boundless. While some think gold reserves are far overestimated, others think something completely different is stored in the vault, like highly classified government documents or even Jimmy Hoffa’s body.
The Government’s Tight Lips

The U.S. Mint will not say what is in Fort Knox, and that just makes people more suspicious. The Treasury Secretary Steve Mnuchin and lawmakers toured the site in 2017, but their vague assurances did nothing to dispel questions over what is there.
More Than Just Gold?

Fort Knox has not only kept gold. It protected the original copies of the Declaration of Independence and the U.S. Constitution during World War II. During the 1990s, it held large amounts of morphine and opium for national security.
Is Fort Knox Still Significant?

America dropped the gold standard in 1971, meaning money in the country is no longer backed by gold. For some, the gold stored at Fort Knox today is merely symbolic and not a critical component of the country’s money system.
A Mystery That Lasts

America’s most mysterious location, whether it contains gold or secrets or not, is Fort Knox. Its access is highly regulated and audits practically never take place, so the world might never find out what is truly behind its 22-ton door.
Sources
Everyone’s talking about Fort Knox: 10 things you probably didn’t know
The mysterious vaults of U.S. Fort Knox