Skydiver Luke Aikins signals to pilot Aaron Fitzgerald as he prepares to jump from a helicopter in Simi Valley, Calif., July 25, 2016. Although he's one of the most accomplished skydivers in the world, Luke Aikins will tell you that his latest jump - out of a plane at 25,000 feet without a parachute - was one crazy stunt. "If I wasn't nervous I would beAikins, who has jumped 18,000 times with a parachute, said recently as he prepared to jump from 25,000 feet without one. He landed safely in a giant net during a live television broadcast. Crazy perhaps, but only the latest in a long line of outrageous endeavors. Here are 10 of the craziest and most dangerous

Evel Knievel is shown in his rocket-powered "Skycycle" on Sept. 8, 1974, before his failed attempt at a highly promoted 3/4-mile leap across Snake Riverin Idaho. The parachute malfunctioned and deployed after takeoff. Strong winds blew the cycle into thelanding him close to the swirling river below. After years of jumping motorcycles over buses, trucks and fountains, and breaking many of his bones, Knievel decided to ride a rocket-powered motorcycle across a mile-wide chasm in Utah's Snake Riveron Sept. 8, 1974. He didn't make it, his cycle crashing on thefloor below. His escape chute deployed prematurely, likely saving his life

In this Oct. 14, 2012, photo provided by Red Bull Stratos, pilot Felix Baumgartner of Austria jumps out of the capsule during the final manned flight for Red Bull Stratos. The Austrian daredevil became the first skydiver to break the speed of sound when he jumped from a small capsule 24 miles above Earth on Oct. 14, 2012, and landed safely on the ground near Roswell, New Mexico, nine minutes later. Aikins helped train Baumgartner for that stunt and was the backup jumper

In this Aug. 7, 1974 file photo, Philippe Petit, a French high wire artist, walks across a tightrope suspended between the World Trade Center's Twin Towers in New York. Philippe Petit and his companions surreptitiously strung a wire between New York City's then-recently constructed World Trade Towers on Aug. 6, 1974, and Petit walked across it the next day. He danced, strutted and clowned around for 45 minutes as startled bystanders watched from 110 stories below. The Frenchman's stunt is the subject of the 2008 documentary "Man on Wire" and the 2015 film "The Walk."

Helen Wallenda, center, arrived home in Sarasota, Fla., on March 23, 1978, with the body of her husband, Karl, and was met by about 25 relatives and circus friends. Helping her off the plane are Marjorie Geiger, left, and Herman Wallenda, Karl's older brother. Aerial performer Karl Wallenda fell to his death at age 73 in a tightrope walk at a hotel in Puerto Rico. The patriarch of the famous German high-wire-walking family plunged to his death on March 22, 1978, while attempting to cross a wire strung between two hotel towers in San Juan, Puerto Rico. Although the 73-year-old Wallenda had performed much more difficult stunts, a wind gust caught him off guard and he fell. In 2012, his great-grandson, Nik Wallenda, became the first person to walk a tightrope across Niagara Falls. And a year later he tight-roped across a gorge near the Grand

In this handout image provided by Red Bull Photofiles, Robbie Maddison jumps his bike more than 100 feet high and to land on the top of the 96-foot-high and 40-foot-deep replica of the Arc de Triomphe in front of Paris Las Vegas on December 31, 2008 in Las Vegas, Nevada. Record-setting Australian motorcycle daredevil Robbie Maddison rang in 2009 by flying his bike 120 feet through the air and landing on Paris Las Vegas hotel's 96-foot-high arch. The feat put a gash in one hand that required 10 stitches. Noting afterward that he'd previously broken his neck, wrist and collarbone doing stunts, Maddison said he considered this injury no more than a paper cut

Dean Potter receives his award for World Alternative Sportsman of the Year on May 20, 2003 during the Laureus World Sports Awards held at the Grimaldi Forum in Monaco. One of the sport's most acclaimed and safety-conscious jumpers, Potter, 43, was attempting a twilight wingsuit leap from Yosemite National Park's Taft Point on May 16, 2015, when something went wrong and he plunged to his death. Graham Hunt, a friend jumping with him, also died. BASE jumping is an acronym for leaping from a building, antenna, span or Earth and is banned in Yosemite, although it occurs there with some regularity. A dangerous stunt led to the death of two daredevils

Johnny Strange arrives at Global Green USA's 8th annual pre-Oscar party "Greener Cities For A Cooler Planet" held at Avalon Feb. 23, 2011, in Hollywood, California. The American adventurer, who at 17 became the youngest person to summit the highest mountains on all seven continents, was 23 last October when he crashed into a mountain in the Swiss Alps while filming a video for a new wingsuit. The day before he'd posted on social media stunning close-to-the-ground photos he'd taken, but he'd also noted the weather had been unpredictable

"Urban climber" Alain Robert has scaled the tallest structures all over the world, often without ropes or harnesses and sometimes illegally. On Christmas Day 2004 he climbed to the top of Taiwan's Taipei 101 Building, which at the time was the world's tallest. Braving rain and wind, he climbed for four hours to get to the top, stopping along the way to chat with Taiwan's president.