Formed over 200 million years ago, the result of a forest being buried by volcanic ash and petrified, the Painted Desert and Petrified Forest National Park makes for a particularly interesting detour off Route 66. The glorious multi-colored rock formations are a result of the various iron and manganese compounds in the rock, and on a sunny day produce vibrant reds and oranges. The views are spectacular and photographs can't do justice to the beauty of the various colored layers - it really has to be seen to be appreciated.
As the only National Park to contain a portion of Route 66, the Petrified Forest has an interesting visitor’s center with plenty of polished examples of petrified wood. As well as being a popular destination for sightseeing, it's also a magnet for photographers, hikers and backpackers.
North of the Petrified Forest you gain access to the Painted Desert - a desert badlands, so called because of the brilliant and varied colors on of rock on display. As you drive through there are many opportunities to pull over in the spaces provided to stretch your legs and take some photos.
For the purposes of your roadtrip, the Painted Desert and Petrified Forest National Park can be treated as one destination - Mother Nature's two-for one!