Route 66 - Petrified Forest National Park

Welcome to the Petrified Forest National Park, Arizona, 230 square miles of desert and Badlands. There's so much to see here over such a wide area that it's probably a trip in its own right. The park has over three-quarters of a million visitors every year, with a good few hiking and backpacking over the course of a few days.

The part was declared a national monument in 1906. Route 66 goes right through it, guaranteeing that casual sightseeing can be done from the comfort of an air-conditioned car! Made a national park in 1962, it's not just notable for the landscape; around 400 species of plants can be found across the park, and in addition to other animals, birdwatchers will be keen to spot over 200 separate species, some migratory, some permanent residents.

But onto the petrified bit - the park is particularly noted for its fossils, not least the fallen trees that give it its name, and which grew during the late Triassic Period, some 225 million years ago. Animal fossils include giant phytosaurs (an extinct group of semi-aquatic reptiles) and a probable sister evolutionary group of the branch from which birds, crocodiles and early dinosaurs descend.

Human habitation came somewhat later, with evidence of tribal groups dating back around 8000 years and farming culture from around 2000 years ago.