To make horses rideable during domestication, people may have inadvertently targeted a mutation in horses to strengthen their backs and their balance.

Levels of hydrogen sulfide gas soared near a raging section of the Tijuana River in San Diego, exposing residents to potentially harmful air pollution.

In late August 2005, Hurricane Katrina devastated the U.S. Gulf Coast. The storm cut a deadly swath through Louisiana, Mississippi and Alabama, deluging coastal towns as surges of ocean water swept ...