The great white shark—a fast, powerful, 16-foot-long torpedo that’s armed to the teeth with teeth—has little to fear except fear itself. But also: killer whales.

For almost 15 years, Salvador Jorgensen from the Monterey Bay Aquarium has been studying great white sharks off the coast of California. He and his colleagues would lure the predators to their boats using bits of old carpet that they had cut in the shape of a seal. When the sharks approached, the team would shoot them with electronic tags that periodically emit ultrasonic signals. Underwater receivers, moored throughout Californian waters, detected these signals as the sharks swam by, allowing the team to track their whereabouts over time.

In the early 2000s Terry Mitchell’s dentist retired. For a while, Mitchell, an electrician in his 50s, stopped seeking dental care altogether. But when one of his wisdom teeth began to ache, he started looking for someone new. An acquaintance recommended John Roger Lund, whose practice was a convenient 10-minute walk from Mitchell’s home, in San Jose, California. Lund’s practice was situated in a one-story building with clay roof tiles that housed several dental offices. The interior was a little dated, but not dingy. The waiting room was small and the decor minimal: some plants and photos, no fish. Lund was a good-looking middle-aged guy with arched eyebrows, round glasses, and graying hair that framed a youthful face. He was charming, chatty, and upbeat. At the time, Mitchell and Lund both owned Chevrolet Chevelles, and they bonded over their mutual love of classic cars.

FALL RIVER, Mass.—Four new members of the House were hanging out at a bar back at the end of 2012, after a long day of new-member orientation at Harvard’s Kennedy School: Joe Kennedy of Massachusetts, Beto O’Rourke of Texas, Tulsi Gabbard of Hawaii, and Eric Swalwell of California.

A woman approached the table, and caught O’Rourke’s eye.

“She’s like, ‘Are you who I think you are?’ And I thought, I just won this seat in Texas and she knows about me, and this is cool. I’m big-time,” O’Rourke told me last year, a few months before his Senate run took off. “And I say, ‘Well, yeah, I think I am.’ She’s like, ‘You’ve got to come over to my table. All my friends want to meet you. This is crazy.’ So I go over and we’re taking pictures.”

Ken Jennings rose to fame after an unprecedented run on Jeopardy 15 years ago: Over the course of 74 episodes, he won a total of roughly $2.5 million.

Recently, a contestant named James Holzhauer has been working toward Jennings’s record at an astonishing pace. After the Friday-evening broadcast of the quiz program, Holzhauer had won about $850,000 over just 12 episodes. If he keeps up that rate, he’ll reach $2.5 million in less than half the time it took Jennings to do so.

Before Holzhauer went on the show, the most money earned in a single episode of Jeopardy was $77,000. During his 12-episode streak, he’s beaten that total not once, but five times, and has set a new record of $131,127. Holzhauer’s success has been attributed not just to his deep trivia knowledge, but also to his aggressive style of play—he homes in on high-value tiles that might contain Daily Doubles, and then often bets enormous sums when he finds them—and his unmatched buzzer-pressing reflexes.

The students have survived watching their teacher demonstrate how to put a condom on a “wooden penis model.” They’ve been assigned homework to find examples of contraception use in sex scenes in movies or TV shows. But before they go, they have one final lesson, one last barrier method for their teacher to sheepishly explain: the dental dam, a latex sheet used as a barrier during oral sex.

According to a sex-ed curriculum used by school districts in San Diego, Boston, Portland, and elsewhere, their teacher would show them how to remove a dam from its package and place it over genitalia by forming an “O” with their hand. The instructor would inform the students that dental dams are flavored, and that they should only be used once and then thrown away. Most important, the teacher would instruct them to always use dental dams when performing oral sex on women, or they’ll be at risk of transmitting STIs.There’s just one problem: The pupils are unlikely ever to take their teachers up on the suggestion. Even the teachers, preaching about the dangers of STIs, have probably never bought one themselves.

A common, low-stakes living-room scenario: A couple is trying to decide on a movie to watch. There’s an option one-half of the relationship is thrilled about, but the other has already seen it. On those grounds, it’s ruled out.

But a new study suggests that this notion that having already seen it—or read it, done it, visited it—automatically precludes a second go-around might be mistaken. Repeating something, it turns out, “may turn out to be less dull than people think,” writes Ed O’Brien, the author of the study and a behavioral-science professor at the University of Chicago’s Booth School of Business.

In one experiment, O’Brien and his research team approached people near an exhibit on genetics at Chicago’s Museum of Science and Industry, asking them to rate how much they enjoyed the exhibit and how much they think they’d enjoy perusing it again. While the subjects tended to predict that the exhibit would be less fun the second time around, the ones who did another walkthrough at the researchers’ request rated it roughly as enjoyable as the first. In other words, the museumgoers, as a group, underestimated how much they would like doing the same thing twice.

News reports suggest that in the coming weeks, the United States and China will sign an agreement that repeals the tariffs the two nations have been levying on each other’s goods for the past nine months. If past behavior is any guide, Donald Trump will call it the greatest deal ever, and global markets will breathe a sigh of relief. But the deal will likely constitute only a modest pause in Washington’s growing hostility toward Beijing.

That’s partly because, for Trump, no agreement is truly final. The president, The New York Times recently observed, “has repeatedly agreed to new trade terms with foreign partners, then talked about undoing those deals to achieve additional goals.” Trump has already begun to renege on commitments made as part of the United States–Mexico–Canada Agreement, which he hailed as “incredible” in October.

It’s been another dizzying few days in Washington, starting with yet another border controversy, as President Donald Trump threatened to bus unauthorized immigrants to sanctuary cities, and ending with the release of Special Counsel Robert Mueller’s report, which turned out to be far more damning than advertised by Trump’s attorney general.

These two very different stories have more in common than meets the eye. In each case, there’s a central tension between the president and aides who refuse to execute orders from him that they believe are illegal or foolish. Mueller’s report is packed with incidents in which White House staff not only didn’t do things Trump said, but never had any intention of doing them. In the case of the border, Immigration and Customs Enforcement staff rebuffed Trump’s plan to bus migrants on legal grounds; meanwhile, Homeland Security Secretary Kirstjen Nielsen and Customs and Border Protection Commissioner Kevin McAleenan refused to turn away migrants seeking asylum, concluding that it was illegal. (Nielsen was sacked soon after, while McAleenan is now her acting replacement.)

Let’s get some things straight.

Passover is a springtime Jewish festival celebrating the early Israelites’ exodus from Egypt and freedom from slavery. Jews observe it by hosting a ritual dinner, called a seder, and then by abstaining from eating all leavened bread for about a week. (Some of us abstain from some other stuff, too.) Instead, we eat matzo, a thin, unleavened cracker.

Easter is a springtime Christian holiday celebrating the resurrection of Jesus Christ and freedom from sin and death. It is preceded by a series of holidays commemorating Jesus’s path to the cross. One of these holidays is Maundy Thursday, which, aside from being a great name for a holiday, is a remembrance of the Last Supper, which was a seder. In the United States, many Christians observe Easter by attending a ritual meal between breakfast and lunch, called a brunch.

Updated on April 19 at 1:28 p.m. ET.

There has never been a town like the one San Francisco is becoming, a place where a single industry composed almost entirely of rich people thoroughly dominates the local economy. Much of the money that’s been squished out of the rest of the world gets funneled by the internet pipes to this little sliver of land on the Pacific Ocean, jutting out into the glory of the bay. The city now sits atop a geyser of cash created from what the scholar Shoshana Zuboff calls “behavioral surplus”—the natural resource created from your behavior, which is to say your mind.

Literal colonies of the working poor now cling to forgotten streets in RV communities. Homeless encampments are stitched onto any liminal plot of land. To lose your apartment doesn’t mean moving one neighborhood over but three cities away, to Antioch or Gilroy or Stockton.