Daredevil walks tightrope across Chicago skyline A DAREDEVIL left spectators with their hearts in their mouths after successfully making two tightrope crossings between some of Chicago's most famous landmarks. Nik Wallenda, who refused to use a harness or safety net, astonished an estimated 50,000 spectators in the streets below after traversing the city's river before embarking on a second walk while blindfolded. In all, the world record breaking back to back walks took less than eight minutes, with viewers from around the globe watching his perilous journey step by tentative step. After reaching terra firma, the 35-year-old - who comes from a family renowned for its thrill seeking exploits - described the experience as "incredible." Mr Wallenda's hazardous walk began at the top of the Marina City west tower, a 65-storey skyscraper some 587 feet high. His destination was the Leo Burnett building on the opposite side of the Chicago river, a 635 foot structure. The height difference meant that Mr Wallenda not only had to contend with a lengthy 454 foot long tightrope, but a 19 degree incline, the steepest ever attempted. As members of the public and media gathered to watch, there was genuine concern that the stunt could go awry. Journalists covering the event signed waivers relinquishing their right to claim emotional distress if they witnessed a catastrophe, while the Discovery Channel used a 10-second delay for the broadcast, which would have allowed producers to cut away if anything went wrong. Mr Wallenda, however, cut a disarmingly relaxed figure, even speaking as he made his way across the tightrope. "I love Chicago and Chicago he definitely loves me," he exclaimed at one point in response to the crowds below. What an amazing roar! Looking on, one spectator, Cynthia Garner, said she knew Mr Wallenda would make it after his first few steps. She said: "It was amazing. I saw it with my own eyes. I was afraid when he first started, but once I saw that he didn't hesitate and just walked, I wasn't scared for him no more. After completing the crossing in less than seven minutes, he prepared for his second walk, where the stakes were even higher. Blindfolded, the showman slowly made his way between the two Marina City towers, a 94 foot crossing he navigated in little more than a minute, despite shaking at times on the wire. Speaking afterwards, Mr Wallenda said strong winds and the steeper than expected angle of the first high wire caused him to hurry his performance. He had practiced at a 15-degree angle but said the extra four degrees proved daunting. "That cable looked like it was going straight up," he recalled. The stunt was one of the most impressive displays yet from the Wallenda clan, revered in daredevil circles for their high risk work. Nik is the great grandson of Karl Wallenda of the famous Flying Wallendas circus family, who once remarked: "Life is on the wire. Everything else is just waiting. His mother, Delilah, even walked the tightrope while she was six months pregnant with him. With risk part of its DNA, the family has experienced tragedy, however. A year before Mr Wallenda was born, Karl fell to his death during a tightrope stunt in Puerto Rico at the age of 73. Rather than acting as a cautionary tale, the latest star of the family views that incident as a challenge. Having walked over the brink of Niagara Falls and across the Little Colorado River Gorge, Mr Wallenda has said he now wants to recreate the 1,200 foot long high-wire walk made famous by his great grandfather, which included not one, but two headstands. "I've trained a bit to do a headstand on the wire, but I've never done it publicly because I've always said if I'm going to do it, I'm going to do it on that walk with him," Mr Wallenda said, explaining that he wants to use vintage film of Karl walk to create the illusion of the two of them sharing the high wire. "My dream is to actually walk the wire with my great-grandfather," he explained.