WHAT: Drug cartel gunmen killed 25 people Thursday in Ciudad Juarez, just across the border from El Paso, Texas. It was their bloodiest single day since 2008. More than 2,100 people have been killed there this year.

WHY: A turf war between the Sinaloa and Juarez drug cartels has made Ciudad Juarez, with its population of 1.3 million, one of the world’s most dangerous cities. Recent graffiti threatened to kill the families of fugitive Sinaloa bosses.

WHAT’S BEING DONE: Record-breaking violence continued despite the thousands of soldiers deployed to the city this year. Federal police, including a special investigative unit, have now taken over Ciudad Juarez security.