KNOW IT ALL: Tuesday's Top 7 Stories at NBC News

From riots to rubble, see the stories we're following today.

SHARE THIS —

Good morning. Here are some of the stories we’re following today:

1. State of emergency declared in Baltimore after fiery riots

Riots and looting erupted after the funeral for Freddie Gray, a 25-year-old Baltimore man who died after suffering a spinal cord injury in police custody. Fifteen police officers were injured in the violence and 27 people were arrested as police vehicles were set ablaze and storefront windows were broken. Maryland Gov. Larry Hogan declared a state of emergency. A daily 10 p.m. ET curfew will begin Tuesday. Read more in NEWS.

2. Police across country on alert after street gang threat

In the midst of the protests and rioting, the Baltimore Police Department said in a statement that they had received a "credible threat" that the Black Guerrilla Family, the Bloods, the Crips and other gangs planned to target police officers. Police departments across the country are being extra cautious in the wake of the announcement. Read more in NEWS.

3. Supreme Court to hear arguments on gay marriage

The Supreme Court plans to argue two questions Tuesday: Can states decline to issue marriage licenses to gay couples? And can states decline to recognize marriage licenses obtained by gay couples in other states? If the same-sex couples who brought the suit win the dispute, marriage for same-sex couples would become legal nationwide. A decision is expected by late June. Read more in NEWS.

4. Nepal earthquake toll rises to about 4,300

Rescuers were still digging bodies out of the rubble in Nepal's capital of Kathmandu after a devastating 7.8 quake hit the region Saturday. The death toll was up to 4,349, but it's impossible to determine how many people are still buried. At least 8 million people have been affected by the disaster. Read more in NEWS.

Nepal Earthquake Devastation Could Cost Billions: Here's How to Help

5. Defense continues in Tsarnaev sentencing trial

Boston Marathon bomber Dzhokhar Tsarnaev's defense team started to argue Monday that he should spend life in prison. The same jury that found him guilty on all 30 counts against him will decide his fate. The prosecution last week argued that Tsarnaev was "determined to be America's worst nightmare" and was unrepentant. Read more in NEWS.

6. Did theater shooter suffer insanity or merely anxiety?

Opening statements in the trial of James Holmes, charged in the deadly 2012 gun rampage at an Aurora, Colorado movie theater, began Monday. The prosecution began by arguing that Holmes, who killed 12 and injured 70, suffered from anxiety, while the defense said he is not guilty by reason of insanity. Read more in NEWS.

7. Corinthian students frustrated over abrupt school closure

Corinthian Colleges sent an email to its 16,000 students Sunday night informing them that all 28 campuses would be closed, effective immediately. Many students took out loans and spent months in courses in an effort to advance their careers, but now they need to find another place to continue their educations. Read more in NEWS.

Nightly Spotlight

The local food movement is trendy, but in one Phoenix community — called Agritopia — it's a way of life. In fact, the path from farm to table measures only a couple of blocks.