This week on "Sunday Morning" (July 18)

Guest host: Lee Cowan

WATCH THE FULL JULY 18 EPISODE!

COVER STORY: What the megadrought means to the American West | Watch VideoFarmers dependent upon water from river systems in the American West are seeing massive cuts in their supply, as reservoirs drop to their lowest levels due to the worst drought to hit the region in 1,200 years. Correspondent Ben Tracy talks with scientists who say there is no quick or easy recovery, and with a California farmer whose livelihood is in danger.

For more info:

Del Bosque Farms, Firebaugh., Calif.Park Williams, HyFiVeS Research Group, UCLAJ.T. Reager, Jet Propulsion Laboratory, California Institute of TechnologyU.S. Drought Monitor, National Drought Mitigation Center, University of Nebraska-Lincoln

WORLD: UNESCO's World Heritage Sites: Protecting the world's treasures | Watch VideoFor nearly 50 years the United Nations Educational, Scientific and Cultural Organization has listed outstanding natural and man-made sites as culturally significant locations worthy of protection. But what does designation as a World Heritage Site actually mean for a glacier or coral reef, or a landmark like the Taj Mahal? Correspondent Conor Knighton treks for answers.

For more info:

UNESCO's World Heritage CentreWorld Heritage ListList of World Heritage in Danger

Vatnajökull National Park, Iceland

MUSIC: Nothing can stop Marilyn Maye | Watch ViewJazz singer Marilyn Maye, who has just turned 93, wasn't about to let a pesky pandemic prevent her from doing what she was put on this Earth to do: sing the Great American Songbook. Correspondent Mo Rocca reports.

For more info:

marilynmaye.combillystritch.comThe Wick Theatre, Boca Raton, Fla.

SUNDAY BEST: Fireflies put on a summertime light show (Video)There's a forest in Tennessee where fireflies put on a show unlike anywhere else. It's no wonder thousands of tourists turn out each year to witness the spectacle of nature's nightlife: a species of synchronous fireflies that flashes in unison. Correspondent Lee Cowan brings us a front row seat. Originally broadcast on July 13, 2014.

For more info:

Great Smoky Mountains National Park (nps.gov)

PASSAGE: Zsa Zsa Gabor's final resting place (Video)Five years after actress Zsa Zsa Gabor died in Los Angeles at age 99, her ashes were brought back to her native Hungary for burial. Lee Cowan reports.

JUSTICE: Why are wrongly-convicted people still imprisoned in Missouri? | Watch Video"48 Hours" correspondent Erin Moriarty talks with two Missouri men, Kevin Strickland and Lamar Johnson, who have served a combined 70 years in prison for murders most people now believe they did not commit. And yet, even though prosecutors have called for their release, innocence may not be enough to earn their freedom – both men are still behind bars. So, what's going on in the state of Missouri?

For more info:

Conviction and Incident Review Unit, St. Louis County Prosecuting AttorneySean O'Brien, University of Missouri Kansas City School of LawConviction Integrity Unit, Jackson County Prosecutors' officeMidwest Innocence ProjectFor information on supporting Lamar Johnson and Kevin Strickland visit their pages at GoFundMe.com

HARTMAN: A master listener (Video)In St. Petersburg, Fla., when Al Nixon started coming to a park bench seven years ago, he needed a quiet place to clear his head. Today, he's providing impromptu therapy sessions, as a trusted confidant and counselor to whoever passes by, simply by demonstrating his skill at listening. Steve Hartman reports.

MOVIES: Matt Damon on "Stillwater" and a return to the movie theater | Watch VideoThe Academy Award-winner is back, starring in the new drama "Stillwater," about an Oklahoma oil rig worker whose daughter is imprisoned in France. Matt Damon talks with correspondent Seth Doane about making the critically-praised film; and how becoming a father of four daughters has changed him as an actor.

To watch a trailer for "Stillwater" click on the video player below.

For more info:

"Stillwater" opens in theaters July 30

HUMOR: Cartoons from The New Yorker (Video)"Sunday Morning" sends you off to the rest of your Sunday with a smile, courtesy of recent cartoons from The New Yorker magazine.

QUARANTINE: Josh Seftel's Mom is ready for a reunion (Video)Throughout the pandemic lockdown, "Sunday Morning" contributor Josh Seftel has been checking in virtually with his mother, Pat. Now, she's ready for an in-person get-together – and a long-awaited chance to meet her newest granddaughter.

For more info:

seftel.com

NATURE: Caddo Lake (Extended Video)"Sunday Morning" takes us to Caddo Lake on the Texas-Louisiana border, home to a flooded forest of bald cypress and water tupelo trees. Videographer: Scot Miller.

WEB EXCLUSIVE:

GALLERY: Pulitzer Prize-winning photojournalist Danish SiddiquiExamine some of the remarkable images from the award-winning photographer, who was killed while embedded among Afghan Special Forces.

The Emmy Award-winning "CBS Sunday Morning" is broadcast on CBS Sundays beginning at 9:00 a.m. ET. Executive producer is Rand Morrison.

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Jill Schlesinger discusses what is behind the "biggest price increases in 30 years"

Face The Nation: Krebs, Schlesinger, Mullen, Becker

Krebs says foreign disinformation actors "don't actually have to do a whole lot because we've done so much here domestically to ourselves”