Daniel Dennis, 25, has an interest in gymnastics and enjoys photography. Put them together, and you have one of the scarier hobbies of this decade: rooftopping. He has been photographed hanging off the sides of skyscrapers or peeking over the ledges of buildings more than a dozen stories tall. His Instagram account shows a blood-pumping, stomach-dropping account of his escapades.
Dennis started rooftopping just two years ago and says he's been on top of every downtown Dallas building except Bank of America.
"There were weeks when I would do it every single day, as soon as I got off work," he says.
He recently moved to Houston — and says he stood on the top of the six tallest buildings there in a single day — but makes regular trips back to Dallas to visit his favorite high-rises. He scavenges the city, usually for six hours at a time, typically in a small group of two or three people.
"It started off as an underground network of photographers and people who explore abandoned buildings," he says. "But then we started infiltrating active places."
Much of their work is done in secret. Dennis puts his camera gear in briefcases or toolboxes to avoid scrutiny from security guards. And some of the adventures involve trespassing onto restricted floors of skyscrapers. (If caught trespassing, Dallas Police Department Senior Cpl. DeMarquis Black says he could be charged with criminal trespass if the building was open, or burglary if a lock was picked or broken.)
Rooftopping is a matter of life and death, and Dennis says he doesn't consider it a silly game. But the imagery and excitement make it worth the risk, he says.
"It's a different perspective and a different view," he says. "But for me, it's a practice in self-control. I do it because I know I can and I have the ability to. I've trained my body to do it. When you're hanging in the air from a skyscraper, it's a powerful feeling of knowing you're in control."
Of course, a rooftopping trip can go wrong.
"The liability involved would jeopardize my livelihood," says photographer Justin Terveen, who is known for his skyline pictures of Dallas but says he doesn't take photographs from dangerous vantage points. When he shoots from rooftops for paid gigs, he says he's sure to get access legally. "It's only a matter of time before someone ends up seriously injured, or worse."
Control is everything. Once, Dennis was walking on the rooftop of a dilapidated building off Martin Luther King Jr. Boulevard that started crumbling; he had to jump to another spot before it caved in. A friend had a close call while hanging off the side of a building by one arm. Dennis was beside him at the time, doing a handstand on the edge.
"He had his fingers wrapped around the metal flashing on the ledge and it started coming off," Dennis explains. "I was actually holding that flashing down, and when I dropped off the handstand, he started falling. But he was able to pull himself up before it completely came off."
Dennis knows the story of Wu Yongning, the famous Chinese rooftopper who fell to his death on video last year. The footage of his final moments went viral and prompted debates about whether the internet video industry was in some way responsible.
On July 12, Hollywood star Will Smith climbed a bridge in Budapest to do the viral dance to the hit Drake song "In My Feelings." He posted drone footage of the stunt on his Instagram account.
But in Dennis' case, he insists he is not reckless.
"I consider myself pretty safe," he says. "The pictures I have of me hanging were carefully thought out. I test the grip, evaluate the conditions and how I feel. Humidity can be a factor." In a Jan. 30 Instagram post, he even cautioned his followers: "Warning! Do not attempt! I've trained for a long time to be able to do this kind of stuff. One slip and it's all over. Each stunt is carefully considered and weighed and judged."
But he has lost a camera. In March, Dennis climbed a long ladder wrapped in razor wire in the dark to reach the top of a government building in downtown Dallas. As he stepped off, his backpack snagged on the wire and tore open. His camera and lenses plunged a few hundred feet and were destroyed on impact. Anyone standing below would've been at risk from the falling debris.
For Joong Won Park, 19, a rooftopper from Seoul who goes by the name Jackson Park, he says rooftopping is about learning to manage fear.
"The fear of security is bigger than the fear of heights," he says. And he corrects a misconception: "I'm addicted to rooftopping, but I don't get an adrenaline rush from it. Adrenaline is something you feel after making a big mistake."
Dennis was actually afraid of heights when he first started. "I was so terrified of the edge that I crawled on my belly and forced myself to look. I can still remember that wrenching feeling in the pit of my stomach as I was getting close to the edge."
But he kept doing it.
"I try to do it in a way that doesn't impact anyone else negatively," he says. "I'm not trying to steal stuff or break stuff or go after company secrets. I just want to take a picture off the roof."
He knew when to take a break, he says. For several weeks after the 2016 ambush of Dallas police officers, Dennis says he didn't go on a roof because it wasn't an appropriate time to walk on an elevated surface, uninvited, after dark.
And Dennis says he's still afraid of heights. But after eight years of gymnastics, with training in balance and grip strength, he believes he has enough control.
"You really are just a step away from death," he says. "But I like seeing things that nobody else gets to see."