Arizona

South of Tucson is the Titan Missile Museum, the only Titan missile silo open to the public — a real 1960s missile silo with a real Titan missile (sans fuel, sans warhead) in it. A guided tour takes you underground to the control center, which was staffed 24/7 and was always ready to fire the missile if the order from the president ever came (and thank goodness it never did). They even demonstrated how to launch it — one officer turns this key over here, while simultaneously another officer turns that key over there. Then there's the walk down the underground tunnel to the silo itself, where you can look in and see the Titan, poised for takeoff. The missile is huge — a hundred feet tall, ten feet in diameter — and the payload was a nine-megaton atom bomb, the largest used in a missile, targeted somewhere in the USSR. You can understand the part Titans played in the Cold War's "balance of terror" or "mutually assured destruction" policy which successfully kept us and Russia from firing a single missile.

Heading north, we drove Interstate 19 and noticed that the road signs show distances in kilometers, not miles!

East of Flagstaff we came upon the Arizona Meteor Crater. Have you visited it? Even heard of it? No? Well, it's worth seeing, because it's four thousand feet in diameter, and five hundred feet deep. In human terms, there's room for 20 football fields in its bottom, and if the Washington Monument were placed in it, the top would be level with the crater's rim. They figure the meteor was 150 feet wide, weighed a million pounds, and came screaming out of the northeast sky at 40,000 miles an hour when it impacted with the equivalent of a 20 megaton bomb. Formed fifty thousand years ago, it's quite well preserved, with little erosion (this part of Arizona has little precipitation) and no glacial bulldozing (Arizona wasn't overrun by glaciers as Minnesota was). Recommended.