Beneath the United States lies a surprising network of caves shaped over millions of years. Some feel almost otherworldly, with strange rock formations and the occasional glow from naturally occurring ...

The CDC's second-in-command, Dr. Ralph Abraham, abruptly stepped down Monday. It's the latest in a string of resignations at the top of the agency.

This unique alkaline lake in Central Washington state is a scenic gem offering fishing, hiking, and dramatic caves in a ...