A weekend crowded with TV choices

Saturday night belongs to the documentary epic “Planet Earth II” (8 p.m., BBC America). Presented a full decade after “Planet Earth,” this new incarnation reflects changes in camera technology that bring viewers even closer to the action, as well as changes to the natural world that are having a dramatic impact on natural habitats.

Narrated by David Attenborough, this stunning production is divided by locations. Tonight’s installment studies islands and their unique ecosystems. Further adventures will explore mountains, jungles, deserts, grasslands and cities — new, entirely man-made environments where animals have learned to adapt with surprising efficiency.

» On a similar note, the new series “The Zoo” (9 p.m. Saturday, Animal Planet) explores the Bronx Zoo, the 265-acre home to more than 6,000 animals and 500 employees and a leading conservation institution located in the heart of America’s biggest city.

» A seven-part murder mystery told in a series of flashbacks, “Big Little Lies” (8 p.m. Sunday, HBO) offers a comeback of sorts for Reese Witherspoon. A dynamic young actress who electrified audiences in offbeat films including “Freeway,” “Election” and “American Psycho,” Witherspoon became a bankable star in the “Legally Blonde” franchise and a respectable Oscar winner in “Walk the Line.” But along the way her movies and her roles became too safe and a little boring.

» Also debuting on HBO, “Crashing” (9:30 p.m. Sunday) stars Pete Holmes as Pete, a would-be stand-up comedy star whose life is upended when he finds his wife and childhood sweetheart, Jessica (Lauren Lapkus), in bed with another man.

Tired of supporting Pete and his fantasies, Jessica takes up with a hilariously hirsute fellow teacher who appears here in his birthday suit. “Crashing” may share producer Judd Apatow with “Girls” (and a taste for full-frontal nudity), but Holmes sports a charmingly goofy modesty nowhere to be found on Lena Dunham’s comedy of narcissism. » CBS premieres the first episode of “The Good Fight” (7 p.m. Sunday, WREG-TV Channel 3), a spinoff of “The Good Wife,” starring Christine Baranski as Diane Lockhart. After this sneak peak, viewers will only be able to follow “The Good Fight” on the CBS All Access subscription streaming service.

» Viceland imports “Trapped” (9 p.m. Sunday) from Iceland as its first scripted series. This 10-part “Nordic noir” murder mystery begins with the discovery of a body floating alongside a Danish freighter.

Saturday’s other highlights

» The voices of Hugh Jackman and Kate Winslet animate the 2006 comedy “Flushed Away” (7 p.m., WATN-TV Channel 24). While critically well received, this expensively produced tale of rats, toilets and sewers did not resonate with viewers.

» Natasha Bassett stars in the 2017 biopic “Britney Ever After” (7 p.m., Lifetime).

Sunday’s other highlights

» Scheduled on “60 Minutes” (6 p.m., WREG-TV Channel 3): allegations of abuse against the doctor for the U.S. gymnastics team; a dangerous defect in America’s most popular hunting rifle; an interview with a North Korean defector.

» The Websters are unprepared for Alice’s homecoming on “The Missing” (7 p.m., Starz). Arguably the most compelling series airing at this moment.

» A peculiar new group is discovered on “The Walking Dead” (8 p.m., AMC).

» Carrie’s home is no refuge on “Homeland” (8 p.m., Showtime).

» Nassau descends into chaos on “Black Sails” (8 p.m., Starz).

» Video games can be murder on “Elementary” (9 p.m., WREG-TV Channel 3).

» Axe ponders his options on the second season premiere of “Billions” (9 p.m., Showtime).

Kevin McDonough can be reached at kevin.tvguy@gmail.com.