US daredevil Nik Wallenda has broken two world records by tightrope walking between three skyscrapers in the Chicago skyline without a safety harness.

Wallenda, the seventh generation of the Flying Wallendas circus family, set records for the steepest tightrope incline and highest blindfolded walk when he crossed the Chicago River.

The adrenaline junkie took seven minutes to walk the 138m between the Marina City west tower and the Leo Burnett Building on a tightrope 204m above the ground and set at an incline of 19 degrees, calmly talking to his team and a reporter waiting for him on the second building.

The 35-year-old high-wire artist then quickly returned to the Marina City west tower and walked blindfolded along a 152m tightrope to the Marina City east tower in just over a minute.

An estimated 50,000 people watched the daredevil complete the stunt, with the event filmed by the Discovery Channel.