Photos: A century of tanks

On Sunday, he visited Fort Knox, an Army base just south of Louisville, Ky., that happens to be the home of the United States Bullion Depository, which itself is usually referred to as Fort Knox.

But the base is also the home of the General George Patton Museum, a comprehensive collection made up mainly of the kind of military hardware that helped make Gen. George S. Patton a household name: tanks.

The collection spans nearly the entire 20th century and a little bit of the 21st, and covers tanks and other weapons from World War I through the current war in Iraq.

This is an American vehicle known as the "Ontos," which the U.S. Army began using in 1955 as a low-cost anti-tank weapon that could be flown on cargo planes. It had a crew of three, six M40A1C 106mm recoilless rifles, and four M8C .50 caliber spotting rifles. It weighed 20,000 pounds and could go 100 miles at 30 mph.