A half century earlier, in 1966, a Houston accountant named Bob Henry told his wife, Billye, that he was tired of city life. He said he wanted to raise their three children in a small town, just as he had been raised.

Leafing through a newspaper, Billye spotted an ad for a property called Camp Landa, a modest thirteen-acre campground with some sagging frame cabins that was for sale in the Hill Country town of New Braunfels, thirty miles north of San Antonio and fifty miles south of Austin. Bob, Billye, and the kids—Gary, Jeff, and Jana—piled into the family’s Ford station wagon and drove to the Landa to give it a look. The camp sat next to the spring-fed Comal River, which gently meanders two and a half miles through New Braunfels before merging with the Guadalupe River. Century-old cedar, oak, and cypress trees were scattered throughout the camp. A light breeze rattled the leaves. “This is paradise,” Bob said, and he struck a deal to buy the Landa that day.

The Henrys moved into a small house on the property, which they renamed the Landa Resort. Billye ran the cafe, and Gary, Jeff, and Jana did odd jobs: sweeping out the cabins, mowing the grass, laying brick, shingling, and grouting. To attract more customers, Bob erected two slides that dumped guests into the Comal.

“I always set out to break all the records. I want to be the first at the bar to buy a drink, and I want to be the first to meet a pretty girl, and I want to be the first at everything. I want to have the biggest, the tallest, and the fastest rides at my parks.”

Like his father, Gary, the eldest child, had a sharp, analytical mind. He would later attend the University of Texas and major in accounting. Jana, the youngest, would attend what was then known as Southwest Texas State University, in nearby San Marcos, and major in fashion merchandising. But Jeff, the middle child, wasn’t interested at all in a formal education. As a boy, he was the classic river rat, a Huck Finn in cutoff shorts who spent almost all his free time on the Comal. He swam, fished, canoed, rafted, and hunted for turtles. He pedaled his bicycle across town to buy busted car-tire inner tubes at gas stations, which he patched up and rented to tourists who wanted to float the river. He gave river tours, and he operated a petting zoo. “Thank you for bringing me here,” he once said to his dad. “This is the best life I could ever imagine.”

Jeff was so busy with his own projects that he barely had time to go to New Braunfels High School, and when he did, he often showed up for class barefoot. He was smart, and he joined the debate team, but he didn’t turn in his homework and refused to take tests, telling his teachers that tests were a waste of time. During his senior year, the school superintendent went to his father and said, “Bob, I have to be honest. We’re not sure how to handle Jeff.” According to family legend, the superintendent then handed Bob a diploma. “Tell Jeff we’re going to let him graduate so that he no longer has to come back to school.”

After high school, Jeff opened a video arcade bar in San Marcos that he called the Too Bitter Bar, the walls of which contained painted murals of moons, watermelons, lips, and bananas. He also kept working for his father. Around this time he noticed that some of the people going down his father’s slides were hitting the water too hard. So he invented what he described as a “water brake,” a dip at the end of the slide that slowed the guests down.

In 1977, when he was 22 years old, he took a trip with a buddy to Orlando, Florida, where he visited two newly opened water parks: Wet ’n Wild and Disney’s River Country. (At that point, there were fewer than a half dozen water parks around the U.S.) Jeff quickly got on the phone to tell Bob and Billye all about it. “He had the ability to see what other people were doing and then take that to the next level,” Gary told me. “And he saw before anyone else what we could do in New Braunfels.”

Courtesy of Schlitterbahn Waterparks and Resorts

Bob loved the idea of a water park. He bought a piece of property next door to the Landa, built a sixty-foot replica of a German castle (to reflect New Braunfels’s heritage), and had four blue fiberglass waterslides erected around the castle. He named the park Schlitterbahn, which means, roughly, “slippery road” in German, and hired his children to help him manage it. The quiet, efficient Gary oversaw the park’s buildings and finances; Jana handled the marketing; and Jeff was in charge of the attractions.

Schlitterbahn opened in 1979, drawing approximately five thousand visitors in its first season (the park is open full-time only from Memorial Day until Labor Day). For Schlitterbahn’s second season, Jeff added a 50,000-square-foot pool and an inner tube ride that he named the Hillside Tube Chute. In subsequent seasons, he built the Cliffhanger Tube Chute, the Tunnel Tube Chute, and the 45-minute-long Raging River Tube Chute. He encircled the park with a man-made river that behaved a lot like a real river, with light rapids, quick drops, and backwater eddies, and he filled the children’s playground with animal sculptures, telescopes, water cannons, giant sand buckets, and small slides that sent kids into shallow pools.

By 1990 Schlitterbahn had become a sensation, drawing nearly 500,000 people a year. Visitors loved the fact that they could park for free and bring their own food and drinks to the picnic areas. And, of course, they loved Jeff’s increasingly daring rides. On a 25-acre piece of property that the Henrys bought, three blocks east of the main park, he erected two rides that he had co-created with a former surfer turned inventor named Tom Lochtefeld. The first was the Boogie Bahn, which allowed riders to actually surf on boogie boards over a thin, fast-flowing sheet of water that shot over a sloped surface. The second was the Dragon Blaster, a watery version of a roller coaster (a “water coaster,” Jeff called it), which used high-pressure jets of water to push tubers up and around chutes instead of just sending them straight downhill. Jeff came up with an artificial river that he called the Torrent River, where large waves unexpectedly rose and broke around the tubers. He later added another water coaster, the Master Blaster, that was six stories tall and filled with thrilling hairpin turns.

The ride quickly became the park’s most popular attraction.

Despite all his success, Jeff remained, at heart, a river rat. Bearded and scruffy, he almost always wore a dirty, creased ball cap, an old fishing shirt, shorts, and muddy boots. He drove an old truck. When he was in meetings, he pulled off his boots and propped his bare feet up on the table. He apparently enjoyed smoking pot. (In 1994 he pleaded guilty to third-degree felony drug possession after he was caught with seventeen ounces of marijuana.) And he was sometimes as obstinate with coworkers as he used to be with his high school teachers. “You could be in his presence for thirty minutes and leave disliking him immensely,” a water park consultant who worked with him told me. “He always thought he was right.”

Yet Jeff made no apologies. He said that if he was demanding and impatient, it was because he was consumed with making Schlitterbahn the best water park in the world. In a black notebook, he constantly wrote down ideas for new rides he wanted to build. To get even more ideas, he pored over the history of Roman aqueducts and leafed through Jules Verne novels. He never got a conventional education beyond high school and never formally studied physics or engineering. And that never worried the people around him. “That would be like someone being concerned that Bill Gates or Mark Zuckerberg doesn’t have a college degree,” his brother told me. “The people that have a spark of genius don’t necessarily need college. Plus, Jeff always surrounded himself with other knowledgeable people who were able to do the numbers work that he wasn’t inclined to do.”

When he wasn’t working on Schlitterbahn rides, Jeff exported his inventions around the world. He sold his technology for slides and river systems to the Atlantis Paradise Island resort in the Bahamas and to the Palm in Dubai. In 1989, at a water park in Brazil, he created a 135-foot-high slide, called Insano, that at the time was the world’s tallest. (A single rider, lying on his back, shot straight down the slide, slowed during the long water brake, and finally came to a stop in a runout pool.) Industry veterans nicknamed him the Lord of the Slides and the Wizard of Wet.

“I always set out to break all the records,” Jeff told USA Today. “I want to be the first at the bar to buy a drink, and I want to be the first to meet a pretty girl, and I want to be the first at everything. I want to have the biggest, the tallest, and the fastest rides at my parks.”

Charlie Riedel/AP

Had Jeff discovered his natural talents in almost any industry other than water parks, he might have had a harder time pushing the limits with his creations. But in the U.S., water park rides are not tightly regulated. Although the federal government’s Consumer Product Safety Commission has the authority to set safety standards for such products as baby cribs and bicycles, it has no authority to regulate water parks. That responsibility lies entirely with the states. Some states have agencies that inspect water parks; others rely on the parks’ own insurance companies to do inspections. Texas law, for instance, says that a park must obtain a $1 million liability policy for each of its rides and must have all rides inspected once a year by an inspector hired by the insurance company. But there is nothing in the law that requires the inspector to have any particular certifications. Nor does the law require an inspector to evaluate the safety of such factors as the ride’s speed or the geometric angle of its slide path. According to Texas Department of Insurance spokesman Jerry Hagins, the inspector is charged only with making sure that the ride is in sound condition and meets the “manufacturer’s specifications.” In other words, a water park is allowed to police itself.

Schlitterbahn initially seemed to be policing itself just fine. In 1998 the New Braunfels Schlitterbahn was named the country’s Best Waterpark in a poll conducted by Amusement Today. Sensing opportunity, the Henrys opened a Schlitterbahn in South Padre Island, in 2001. Jeff’s job was to fill the park with new attractions, and he didn’t disappoint. He devised a complicated artificial river system that moved tubers from one major slide to the next so they would rarely need to leave the water to stand in line.

In 2006 the Henrys expanded again, opening a year-round park in Galveston with a retractable roof. By then, developers from around the country who also wanted a Schlitterbahn were regularly approaching the Henry family with proposals. One of the most intriguing came from a Kansas City investor. He asked the Henrys to build a Schlitterbahn water park in Wyandotte County, Kansas, which covers the western half of metro Kansas City. The plans would eventually call for hotels, rental cabins, hundreds of thousands of square feet of retail outlets, and a residential area surrounding the park. To get the project going, a real estate investment trust offered to loan the Henrys $174.3 million. The State of Kansas also agreed to throw in an estimated $200 million in sales tax revenue bonds. These were Disneylike numbers. Schlitterbahn was entering the big leagues of American entertainment.

The deal was announced in 2005, but because of a drawn-out construction process, as well as the economic downturn of 2008, the venture had to be scaled back significantly, with no hotels, no homes, and little retail. When the park opened in 2009, expanses of dirt surrounded much of it. Industry insiders said the Kansas City Schlitterbahn needed a jolt—something big, really big—that would help it live up to the early hype and investment.

In October 2012, Jeff was at an amusement park industry trade show with his chief collaborator, John Schooley, a soft-spoken, silver-haired former yacht builder who had constructed slides at water parks in Asia before coming to New Braunfels to work for Jeff in 1998. The two men were approached by producers from the Travel Channel who said they were looking for an episode to lead off the new season of their popular TV series Xtreme Waterparks. They asked Jeff if he had any projects in the works.

Jeff, who has a streak of P. T. Barnum in him, suddenly blurted out that he and Schooley were going to build the world’s tallest and fastest waterslide at the Kansas City Schlitterbahn.

This was news to everyone, even at Schlitterbahn. For nearly a decade, Jeff and Schooley had been working on what they called a cannon nozzle: a highly pressurized water nozzle, much more advanced than the ones used in the Dragon Blaster and Master Blaster, that would propel riders up higher hills. They had no immediate plans to build a ride using the cannon nozzle, and certainly had no plans to build it in Kansas City, until Jeff made his pronouncement to the Travel Channel producers. “Something clicked in my head, and I just realized the time had come to do it,” he told me later.

He returned to Texas and met with Gary and Jana. (By this time, Bob had handed off the company to his three children, giving each of them a third of the voting shares.) He sketched out his plan for Verrückt: a one-of-a-kind slide that would not only send riders almost straight down a staggeringly tall hill but also shoot them up and over a second imposing hill, giving people multiple heart-stopping thrills. The slide would become the talk of the amusement park industry, he said.

Gary and Jana agreed that Jeff should proceed with Verrückt. Soon, reporters from an array of media outlets—USA Today, Wired, ESPN’s Grantland, even Smithsonian magazine—were calling to ask Jeff about his latest adventure, and he was always ready with a good quote. He told one reporter that Verrückt was “an erotic piece of art” and would go down in history as “the most terrifying ride ever built in a water park.” He told another reporter that he had conceived of Verrückt because he could no longer tolerate the thought of the world’s tallest slide being in Brazil. (After he had created the 135-foot Insano, a Brazilian company built a body slide that was just under 164 feet.) “I’m from Texas,” he said later. “It was a matter of pride.”