Two days after a deadly stabbing attack at a crowded mall in Sydney, the police in Australia said they had arrested a man on suspicion of stabbing multiple people during Mass at a church in a suburb west of the city. A police operation was underway after 7:10 p.m. local time on Monday, the New South Wales Police Force said …

The world’s coral reefs are in the throes of a global bleaching event caused by extraordinary ocean temperatures, the National Oceanic and Atmospheric Administration and international partners announced Monday. It is the fourth such global event on record and is expected to affect more reefs than any other. Bleaching occurs when corals become so stressed that they lose the symbiotic …

When Iran agreed to a deal in 2015 that would require it to surrender 97 percent of the uranium it could use to make nuclear bombs, Russia and China worked alongside the United States and Europe to get the pact done. The Russians even took Iran’s nuclear fuel, for a hefty fee, prompting celebratory declarations that President Vladimir V. Putin …