Agate Bridge — the most famous of the individual petrified tree specimens in the Petrified Forest, now part of a U.S. national park near Holbrook in Arizona’s remote Navajo and Apache counties. The park is replete with fossils, especially fallen trees, or parts of them, that lived in the Late Triassic Period, about 225 million years ago. The park’s splendors — which now include colorful badlands called the Painted Desert — so impressed early preservationists that they were the second-ever site designated a protected national monument (later national park) after President Theodore Roosevelt signed the authorization in 1906. Photo by Carol Highsmith, 2018.