The federal agency has a broad mandate to protect Americans’ health and an expansive global reach. But the COVID-19 pandemic has been one of its most daunting challenges.

Tens of millions of Chinese now identify as Christians, and the number has grown rapidly, posing challenges for a government that is officially atheist and wary of threats to its power.

Poland has maintained economic growth despite the global financial crisis and eurozone woes, while asserting itself as a leading advocate for greater European integration.