Petrified Forest National Park
The Petrified Forest National Park in Arizona was declared a national monument by President Theodore Roosevelt in 1906. The natural phenomenon is the remains of a 225 million-year-old forest inhabited by dinosaurs, predatory amphibians, and huge reptiles. The petrified remains of some of them are found here. In some places there are exposed layers of fossils, 92 m thick. The Rainbow Forest Museum has collected a fantastic collection of fossils, including dinosaurs.