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

From Vienna to Pluto, see the stories we're following today.

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

1. Iran and World Powers Reach Nuclear Pact

Iran and world powers reached a historic deal early Tuesday for Tehran to curb its nuclear program in exchange for the easing of economic sanctions, capping a decade-long dispute. President Obama said the accord makes the world "safer and more secure." Read more in NEWS.

2. Mexico Offers $3.8 Million for ‘El Chapo’

Mexican officials are offering a $3.8 million reward for drug kingpin Joaquin Guzman, who broke out of prison Saturday. Authorities said that the cartel chief must have had inside help in the break out. Three prison officials — including the prison's director — have been dismissed. Read more in NEWS.

3. Harper Lee's ‘Go Set a Watchman’ Hits Shelves

Harper Lee's long-awaited second book, written before "To Kill a Mockingbird" but only recently discovered, was released early Tuesday. But some fans are rattled that beloved civil-rights crusader Atticus Finch appears in the new novel as a bitter racist. Read more in NEWS.

4. NYC Reaches Settlement With Eric Garner’s Family

New York City reached a $5.9 million deal with the family of Eric Garner, the man who died after being put in an apparent chokehold by a police officer nearly a year ago. The confrontation, over Garner allegedly selling untaxed cigarettes, was caught on video in which Garner can be heard repeatedly saying "I can't breathe." Read more in NEWS.

5. Boston Cop's Son Busted for Alleged Terror Plot

A Boston police captain's son — reported to be mentally ill and obsessed with Islam — has been charged in an ISIS-inspired plot to set off pressure-cooker bombs at college cafeterias. Boston police captain Robert Ciccolo alerted the FBI that his son, Alexander Ciccolo, 23, had an interest in ISIS. Read more in NEWS.

6. Pentagon Preps to Lift Military Transgender Ban

Defense Secretary Ash Carter announced Monday that the services have six months to figure out the logistics of integrating transgender troops into the military. There is currently a ban on transgender individuals serving in the military, but Carter called the ban an "outdated" approach. Read more in NEWS.

7. New Horizons Probe Examines Pluto

Ahead of its flyby Tuesday, the New Horizons spacecraft was already gathering information about Pluto. The mission has so far found that Pluto is larger than originally thought and quite icy. New Horizons made its close flyby at 7:49 a.m. ET Tuesday. Read more in SCIENCE.

8. Nightly Spotlight: Watch Baby See With Glasses for First Time

This video is clearly cute. A baby seeing for the first time with glasses has an adorable reaction.