Here's a roundup of news trending across the nation and world today.

What to know now:

1. Russia knew about chemicals: U.S. officials say they believe that Russia knew in advance that the Syrian government planned to use chemical weapons in an attack last week, then bombed a hospital after the attack to cover it up. According to The Associated Press, a Russian-operated drone flew over a hospital where victims of the attack were taken, then later, a Russian-made jet bombed the building. A U.S. official who spoke to the AP said the bombing was an attempt to hide the fact that chemical weapons were used. Nearly 100 people were killed in the attack, and hundreds were sickened.

2. San Bernardino school shooting: A man walked into a Southern California elementary school classroom and shot and killed his wife and an 8-year-old student Monday. Cedric Anderson then shot and killed himself, according to authorities. Anderson had not been married to Karen Smith long before he killed her, police said. They have not revealed a motive for the shooting. The shooting left a second child critically injured.

3. Alabama governor resigns: Alabama Gov. Robert Bentley resigned Monday, hours before an impeachment hearing was set to begin. Bentley, who allegedly had an affair with an aide and used state money to hide it, was succeeded by Lt. Gov. Kay Ivey. Ivey becomes the second woman in the state's history to serve as governor. "Today is both a dark day for Alabama, yet also one of opportunity," Ivey said, adding that her "administration will be open, it will be transparent and it will be honest." Ivey will hold the position until the next election in 2018.

4. Roof sentenced: Dylann Roof was sentenced to nine life terms Monday for a killing spree at a historically black church in Charleston, S.C. in 2015. Roof, 23, has already been sentenced to death in federal court for the shootings at the Emanuel AME Church.

5. Manhunt continues: The hunt for a man who stole at least 16 rifles and handguns from a Wisconsin gun shop has moved into its sixth day. Authorities are looking for Joseph Jakubowski, a Wisconsin man who sent a 161-page manifesto railing against the government to President Donald Trump. According to authorities, Jakubowski is "highly agitated."

And one more

The head of the FCC said Monday that in-flight cellphone calls should continue to be banned so that the American traveling public can have "a moment of quiet at 30,000 feet." FCC chairman Ajit Pai, talking about a plan to reverse the ban on making calls from an airplane, said, "I do not believe that moving forward with this plan is in the public interest. Taking it off the table permanently will be a victory for Americans across the country who, like me, value a moment of quiet at 30,000 feet."

In case you missed it

Here’s the video from United Airlines that everyone is talking about.