The U.S. is the only country allowed to withdraw from the World Health Organization. And Jan. 22 is the day when Trump's pullout announcement should go into effect. But ... it's complicated.

It's unclear how many leaders have been asked to join the board, and the large number of invitations being sent out, including to countries that don't get along, has raised questions about the board's mandate and decision-making processes.

Warming temperatures are forcing Antarctic penguins to breed earlier and that's a big problem for two of the cute tuxedoed species that face extinction by the end of the century, a study said.

In his second term, the president is embracing a foreign policy that breaks sharply from U.S. tradition. Both supporters and critics say he's upending a global system in place for 80 years.

There has been a lot of conversation on social media about the downsides of polyester. But are those downsides as bad as they're believed to be? Are there upsides?

Like President Trump, lawmakers around the U.S. blame corporate homebuyers for high prices and want to restrict them. Experts say it's not so simple, and passing laws has proved difficult.

The three most-senior cardinals leading U.S. archdioceses issued the rebuke in a joint statement on Monday, saying recent policies have thrown America's "moral role in confronting evil" into question.

A bipartisan congressional delegation traveled to Denmark to try to deescalate rising tensions. Just as they were finishing, President Trump announced new tariffs on the country until it agrees to his plan of acquiring Greenland.

New research is underway to test whether a combination of high-intensity interval training and generic medicines can slow down aging and fend off age-related diseases. Here's how it might work.

The move comes after President Trump again threatened to invoke the Insurrection Act to control ongoing protests over the immigration enforcement surge in Minneapolis.