Times were already tense. President Nixon had resigned less than a year earlier. The Vietnam War had just come to its bitter end. Unemployment swelled to 8 million, the highest level since the end of the Depression.

Then things got weird. A woman in her twenties reportedly fainted at a movie theater in Wheaton. At another theater in Riverdale, people too nervous to sit in their seats stood in the back, closer to the exits. Someone fled the place, telling a manager she was on tranquilizers and couldn't take it anymore.

It was June 1975. It was the summer of "Jaws."

The Steven Spielberg film about a great white shark that terrorizes a New England resort town did more than pioneer a genre -- the mega-budget, thrill-heavy blockbuster known as the Summer Movie. It made a summer memorable. Caught up in a national phenomenon, Washington area residents spent their sunny weeks in pursuit of a rather unlikely common goal: to scare themselves silly. In a region that typically slows down and empties out between Memorial Day and Labor Day, some summers can make a difference.

The summer of '75 did.

Nearly 30 years later, theater managers long retired from the business still remember the day "Jaws" opened to screaming audiences and endless lines at five Washington area cinemas: Friday, June 20, 1975. The movie grossed nearly $700,000 locally by its third week. Scalpers were spotted at a Vienna theater selling $2.50 tickets for $8, and people were calling the Riverdale Plaza, offering $20 to workers for sold-out seats.

"It was absolute bedlam," recalled Nathan Shor, 76, who used to own the Aspen Hill I and II in Wheaton, now a CVS pharmacy. "They were lined up in front of that theater from early morning to late at night. I don't mean a line. I mean hordes of people."

Douglas Gomery, a professor of mass communication at the University of Maryland who has written extensively about the movie, said there was a name for all that hysteria: shark mania.

The movie, boosted by an unprecedented TV advertising campaign, captured imaginations and ticket sales by toying with people's natural fears of swimming in the ocean, mixing humor and horror with a tense, churning score by John Williams. On vacation from work and school, moviegoers of all ages willingly traded the sunshine for a 124-minute thrill in a darkened room, an experience Hollywood has tried to replicate with varying degrees of success every summer since. Of the 10 highest-grossing movies in the U.S., six were released in the ever-expanding summer movie season, according to the Internet Movie Database.

"It was a defining moment," Gomery said, "no question about it. That summer, everybody had to see 'Jaws.' "

In the beach communities to which Washington residents flock, the movie had an immediate effect. Recreational shark fishermen grumble about the summer that spawned what one called the "Jaws syndrome," when their quiet pastime was invaded by droves of Johnny-come-latelies who didn't respect the ravenous fish. And Butch Arbin, then a teenage lifeguard patrolling the beaches of Ocean City, noticed swimmers sticking close to shore, reluctant to venture out too far.

No one at the time could recall a shark attack in Ocean City, and the most dangerous beasts the lifeguards had to warn tourists about were Portuguese man-of-war stinging jellyfish. It didn't matter. Arbin, now 47 and the captain of the Ocean City Beach Patrol, can still picture the bashful crowds in the water that summer.

"People wouldn't go out much deeper than waist-deep," said Arbin, standing barefoot in the sand Saturday. Through his orange-tinted, square-frame sunglasses, Arbin detected no such hesitation in the tourists and party-hearty teenagers at the beach on this hot, sticky afternoon.

But as he looked out into the sea, there was some commotion in the distance. Bare-chested men were sprinting out of the water as people yelled and screamed. Arbin rushed in, standing ankle-deep in the water. Great white? Stinging jellyfish? Nope, just lifeguard candidates completing a long swim.

It's hard to imagine anything keeping people away from the surf and sand of a city named Ocean, much less a mechanical shark on a silver screen. In 1975, Ocean City's mayor at the time, a charismatic booster fond of flame-red suits, had no intention of seeing "Jaws." "I'm not interested in fantasy," Harry Kelley told The Washington Post.

Kelley and other city leaders didn't worry about the movie clearing the beaches that summer. They were more concerned about another creature of the beach, the shirtless man. Days before "Jaws" opened, the City Council upheld an indecent-exposure ordinance prohibiting anyone older than 10 from appearing topless west of the beach.

Times have changed in the Eastern Shore resort. The late Kelley has a bridge into town named after him, and Arbin now has two pagers, a walkie-talkie and a cell phone clipped to the waistband of his blue trunks. Mayor James Mathias has not made the topless-men issue a priority; he runs a T-shirt shop on the boardwalk.

But Mathias said he did learn a valuable lesson from "Jaws." In the movie, the fictional town's mayor worries that the shark attacks will hurt tourism and tries his best to play down the dangers. "The movie was a piece of entertainment for most of America," Mathias said. "But for some of us who lived at the beach and take public safety so seriously, it was an example of what not to do."

Fatal shark attacks, a rare occurrence along the Eastern Seaboard, did become a frightening reality in 2001. Two attacks over the Labor Day weekend that year killed a 10-year-old boy in Virginia Beach and a 28-year-old man swimming off North Carolina's Outer Banks. But for all the fear of going into the water that "Jaws" and 2001's so-called "summer of the shark" generated, the Florida Museum of Natural History's International Shark Attack File offered some perspective.

In Maryland, for instance, 116 people were killed by lightning strikes from 1959 to 1994. How many were killed by sharks in that time? Zero. In Virginia, there were 51 lightning fatalities in that period, but only one shark attack and no shark-related fatalities, according to the International Shark Attack File.

Such statistics might have calmed the crowds that flocked to see the movie in Ocean City back in 1975. But maybe not. The weekly Beachcomber dispatched a reporter and photographer to one of the first showings and ran pictures of the audience's reaction as they watched the screen, their "jaws agape, eyes as big as silver dollars, looking as if they had probably been electrocuted," said its former editor, Gee Williams, 55.

It was a few summers later, in June 1978, when another shark movie opened in the Washington area and beyond. But the film didn't create as memorable a summer.

It was called "Jaws 2."

Staff researcher Bobbye Pratt contributed to this report.

The Crowds: A massive advertising blitz helped draw moviegoers.

The Movie: "Jaws" made $260 million and pioneered a genre, the summer blockbuster.

The lifeguard: Butch Arbin patrolled the shores during the film's run. "People wouldn't go out much deeper than waist-deep."

Butch Arbin, an Ocean City lifeguard, recalls that crowds during the release of "Jaws" were more timid than now.