Not only has there never been a successful robbery of Fort Knox, but no one has even attempted it since the vault opened in 1935.
There are no visitors allowed. Even if you could somehow get past the military checkpoints, the armed garrisons, and the hundreds of tons of concrete, granite and steel encasing the gold vault, you would be in for a heavy surprise.
There are 4.2 million kilograms (9.2 million pounds) of gold currently stored at Fort Knox. That’s the equivalent of about 338,710 gold bars, each weighing 12.4 kilograms (27.4 pounds).
In short, you would need an army and a caravan of armoured trucks to steal the loot.