at today's rate of steel production (1.3 billion tonnes annually), it would take 833,315 years to produce enough steel to begin work. So once someone notices what you're up to, you have to fend them off for 800 millennia before you have a chance to fight back. In context, it takes under an hour to get the steel for HMS Illustrious.
Oh, and the cost of the steel alone? At 2012 prices, about $852,000,000,000,000,000. Or roughly 13,000 times the world's GDP.
Of course, that's only the price of steel, what about building costs, electric, etc.? That's a big price to pay for a little intimidation and destruction.
Link Via The Daily What