SATURDAY: The famed British wildlife photographer (Animals Up Close With Bertie Gregory) gets wet in a dazzling special launching 25 original hours of the annual Sharkfest extravaganza. In the special, Gregory travels to South Africa to brave the shallows and swim among great white sharks minus the usual protective cage to better capture the marine predators in their natural habitat. Followed by the premieres of two six-part series: Investigation Shark Attack (9/8c), with a report on “California Great Whites,” and Super Shark Highway (10/9c), which explores two of Australia’s busiest shark migration routes.

SUNDAY: What’s love got to do with it? Apparently not a lot in the late 1880s, as poor rich girl Gladys Russell (Taissa Farmiga) finds herself a mere pawn in the negotiations between her robber-baron father George (Morgan Spector) and a money-hungry Duke of Buckingham (Ben Lamb), who seeks her hand and fortune if not her heart. In a happier development, Peggy Scott (Denée Benton) is wooed by handsome Dr. Kirkland (Jordan Donica) in Newport. But will her family’s more modest pedigree pass muster with his parents, played by Broadway royalty, Brian Stokes Mitchell and Phylicia Rashad? The episode title says it all: “Love Is Never Easy.”

SUNDAY: From MLB Studios, a new documentary revisits the history of the Home Run Derby, and the mythic allure of the home run itself, as a curtain raiser to the annual event, scheduled for July 14 at Atlanta’s Truist Park on the eve of the MLB All-Star Game. The Daily Show veteran Roy Wood Jr. hosts the special, with commentary from players including Home Run Derby champs Pete Alonso and Teoscar Hernández plus Mookie Betts, Freddie Freeman, Jazz Chisholm and broadcasters Chris Berman and Bob Costas. Baseball great Albert Pujols, who hit 703 career home runs, makes a special appearance.

SUNDAY: In one of the season’s stronger episodes, Alphy (Rishi Nair) leaves the vicarage to visit a place with which he has a deep personal connection: a home for foundlings that’s on the chopping block to be closed. His dear friend the Rev. Stuart Potts (Downton Abbey‘s Paul Copley) barely seems in control of the children, who manifest their concern about losing their home with bizarre behaviors including voodoo dolls and a Ouija board. When a death occurs, Alphy calls in DI Georgie (Robson Green), who gains crucial new insight into Alphy’s past. Back in Grantchester, Georgie’s wife Cathy (Kacey Ainsworth) makes a bold career move, while housekeeper Mrs. C (Tessa Peake-Jones) becomes understandably concerned about Leonard’s (Al Weaver) drinking.

SUNDAY: On its 50th anniversary, the comedy troupe’s delirious reimagining of the King Arthur legend forms the first half of a Monty Python double feature starting at 8/7c. Come for the Knights who say “Ni!” and stay for the even more irreverent Monty Python’s Life of Brian (10/9c) from 1979.

INSIDE WEEKEND TV:

• Mutual of Omaha’s Wild Kingdom (Sunday, 7 am/6c, MeTV): The legendary wildlife program joins the Sunday morning lineup in a three-hour block to 10 am/9c.
• The Rookie (Sunday, 9/8c, UPtv): The cable channel welcomes all seven seasons of the long-running ABC crime drama with a daylong marathon. The regular schedule: Monday to Friday from 7/6c to 11/10c, and weekends from 3 pm/2c to 11/10c.
• Patience (Sunday, 8/7c, PBS): Patience (Ella Maisy Purvis) grew up studying crime fiction, and now that she’s an investigative assistant for the York police, she’s delighted to help them solve a classic “locked room mystery” involving the death of one of her literary heroes.
• 90 Day Fiancé: Happily Ever After? (Sunday, 8/7c, TLC): The spinoff’s ninth season follows eight fan-favorite couples as they settle into everyday real life once the honeymoon phase has ended.
• Nautilus (Sunday, 9/8c, AMC): Richard E. Grant guest-stars in the swashbuckling fantasy as a gregarious “White Rajah” who encounters Capt. Nemo (Shazad Latif) and the Nautilus crew when they make landfall at Karajaan to replenish supplies. He says he’s no friend of the East India Mercantile Company and has information about Nemo’s family, but can he be trusted?