8. Irradiating Fort Knox's Gold - Goldfinger
In Goldfinger, James Bond learns that a German tycoon called Auric Goldfinger aims to break into Fort Knox. Assuming he plans to steal the vault's gold, Bond confronts the maniacal mogul and explains that his scheme won't work. Because there is nearly 13,000 tons of gold in the facility, there's no way Goldfinger could steal it all before the army intervened.
But Goldfinger isn't going to steal the gold; he's going to irradiate it. His plan is to set off a dirty bomb in the US Bullion Depository in Fort Knox, making billions of dollars worth of gold inert for half a century. This would cause Goldfinger's own gold to skyrocket while the economy collapses.
Even though most Bond villain plans are fantastical, this one is theoretically possible. Jean-Jacques Dethier, who is an economist for the World Bank, stated Goldfinger's scheme is pretty solid. What's really interesting is that Goldfinger WAS intending to steal the gold in the novel and the original script.
When the filmmakers realised the logistics of such a crime would be impossible, they altered Goldfinger's plan to make it more realistic.