Audience for Wallenda's Chicago stunt for Discovery falls short of his 2013 Grand Canyon walk

Nik Wallenda's high-wire act in Chicago boosted Discovery Channel's audience on Sunday.

But the Nielsen ratings company says viewer interest in his lofty feats fell far short of his "Skywire" stunt over the Grand Canyon last year.

Wallenda's Chicago walks aired live Sunday across the U.S.

His first walk between skyscrapers was from 8:35 to 8:42 p.m. Eastern and attracted 5.8 million viewers. His blindfolded walk from 9:01 to 9:03 p.m. Eastern delivered 6.7 million viewers. Those events and the 13-minute break in between were seen by an average of 5.8 million viewers.

By contrast, 13 million people watched his Grand Canyon walk in June 2013. An average of nearly 10.7 million watched the 23-minute walk and stayed through the end of the telecast.