Researchers have succeeded in constructing, from scattered data, a world map of the diversity of tree species. Climate plays a central role for its global distribution; however, the number of species ...

Joshua Tree National Park is often described as an out-of-this-world experience or healing for one’s soul, says Donovan Smith, the park’s public information officer. “With blue sunny skies almost year ...

Since Philadelphia is arranged on a grid system, the mostly one-way roads are easy to navigate. Helpful maps are posted along street corners across the city – watch for the "Walk! Philadelphia" signs ...

Chicago's eastern boundary is formed by Lake Michigan, and the city is divided by the Chicago River into three geographic sections: the North Side, the South Side and the West Side. These sections ...