Chicago and the world watched in awe as daredevil Nik Wallenda performed two heart-stopping skyscraper crossings Sunday on high wires without a harness or safety net, reports the StarTribune.

He even performed one high wire crossing blindfolded.

"I feel incredible," Wallenda told the press at a news conference in a nearby hotel after the event.

He admitted strong winds and the steeper-than-anticipated angle of the first high wire caused him anxiety during the aerial feat. Wallenda had practiced at a 15-degree angle but said the actual 19 degree angle "looked like it was going straight up."

Thousands of people crowded the streets around the city's Marina City towers to watch Wallenda, 35, complete the two tightrope walks.

The chilly conditions in Chicago did not seem to affect Wallenda who lives in Florida.

Wallenda walked the first high wire that stretched 454 feet from the Marina City west tower to the rooftop of a building on the other side of the river. He completed the walk in about six and a half minutes.

Wallenda performed the second high wire walk 543 feet from the ground between the two Marina City towers while blindfolded. He walked the 94-foot wire length in little more than a minute.

As Wallenda stepped off the wire, he ripped off his blindfold and waved. The crowd cheered.

Roughly 13 million viewers tuned in to watch his two previous televised tightrope walks:

1. In 2012, he walked over the brink of Niagara Falls.

2. In 2013, he walked across the Little Colorado River Gorge.

What's next for the heir to the Flying Wallendas' family business? Wallenda wants to recreate a 1,200-foot-long high wire walk with two headstands at Tallulah Falls Gorge in Georgia-a walk made famous by his great-grandfather.

"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," Wallenda said, explaining that he intends to use vintage film of Karl Wallenda's walk to create the illusion of them performing together on the high wire.

A year before Wallenda was born, Karl Wallenda, 73, fell to his death while performing a tightrope stunt in Puerto Rico.