Several historically Black colleges and universities canceled classes and events on Friday after a series of threats. The F.B.I. said the calls were hoaxes.

© Eve Edelheit for The New York Times

The blue dragons, which pack a ferocious sting, have led to several beach closures. Experts say it’s a worrying sign of the warming of the Mediterranean.

© Policía Local Guardamar

A section of the railway bridge, under construction in the country’s northwest, plunged into the Yellow River early on Friday.

© Li Zhanyi/Xinhua, via Associated Press