US Bullion Depository – Fort Knox, Kentucky
Fort Knox has served multiple purposes throughout US history and plenty of conspiracy theorists have come up with pretty fantastical ideas of what actually lies inside (alien spaceships, anyone?). However, what we do know about Fort Knox is that it’s an important safeguard for America’s gold. It holds 2.4% of the world’s refined gold – that doesn’t seem like a lot but that’s more gold holdings than any other country.