1) “OceanXplorers” debut, 9 p.m., National Geographic. James Cameron takes a big-budget, big-ambition approach to deep-sea exploration. Cameron – the director of “Titanic,” “Terminator” and “Avatar” – has a high-tech ship (shown here), two mini-subs and a helicopter. Over six Sundays, it follows whales, sharks and more.
2) “Snowpiercer,” 9 p.m., AMC; rerunning at 11:07. Last week, Layton’s foolish mission – risking all the lives in New Eden, while trying to save his daughter – hit a snag. Now there’s a bigger one – a jolt for him and for viewers. The episode closes with fierce action.
3) “Orphan Black: Echoes,” 10:07 p.m., AMC and BBC America. Last week ended with Craig being shot. Now that triggers some dark memories for Jules. What follows, setting up next week’s finale, is a morose hour, salvaged by superb performances by Amanda Fix (as Jules), Keeley Hawes (Kira) and more.
4) Movies. At 7 p.m., CW’s “The American President” has Michael Douglas and a clever Aaron Sorkin script. At 8:30, ABC’s “Jungle Cruise” is a fun trifle with Dwayne Johnson and Emily Blunt. And Turner Classic Movies has Katharine Hepburn, from “Little Women” (1933) at 9:30 a.m. ET to “On Golden Pond” (1981) at 6.
5) ALSO: It’s football time (already), with a Saints-49ers pre-season game, at 8 p.m. ET on Fox. At 9 and 10 p.m., PBS has the mid-section of the terrific “Magpie Murders.” And at 10, HBO starts “Chimp Crazy, a four-week documentary about a woman’s fight to keep her chimp.