Like its namesake, Fort Knox holds a substantial amount of gold, about 4 million ounces, to be specific. But the treasure is microscopic in size, locked up in quartz rock and buried hundreds of feet underground. Visitors also walk through the mill building, where huge machines crush the rock at a rate of 40,000 tons a day. Fort Knox tours, which are scheduled five days a week, last about two hours. No fee is charged, but reservations are required.
Priority is given to educational and service groups.