Secure against what? You might be surprised at what a wench and a truck can pull / destroy. If that fails, there are shotguns and also explosives, jackhammers and the like.
There are always assumptions built into lock design. A simple lock is very secure if a fence is jumpable, most people will jump the fence rather than mess with a lock.
Even a complex lock will never be secure for national secrets (like nuclear missiles), you need to just assign guards. Locks exist but are basically a formality (IIRC, many tanks and airplanes are left unlocked because all the security posture is with the military and the lock itself is too much of a hassle for logistics).
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Fort Knox itself was designed to be safe from Nazi invasion. If the Nazis invaded New York City, they won't find any of the governments gold. The 'lock' in this case is the miles and miles of geography the Nazis would have to navigate before reaching Fort Knox.
"In 1933, the U.S. suspended gold convertibility and gold exports. In the following year, the U.S. dollar was devalued when the gold price was fixed at $35 per troy ounce. After the U.S. dollar devaluation, so much gold began to flow into the United States that the country’s gold reserves quadrupled within eight years. Notice that this is several years before the outbreak of World War II and predates a large trade surplus in the late 1940s. [...] In 1930, the U.S. controlled about 40% of the world’s gold reserves, but by 1950, the U.S. controlled nearly two-thirds of the world’s gold reserves."
https://www.stlouisfed.org/publications/regional-economist/f...
> what a wench and a truck can pull / destroy.
According to legend, a wench can destroy a whole city state (Troy)!
Evil villains trying to destroy the world know it too, it's why they hire so many wenchmen.
> If the Nazis invaded New York City, they won't find any of the governments gold.
Is that because it’s not actually in Fort Knox? :P