While many broadcast networks suffered with lackluster results on the last Sunday in June, Discovery Channel had no trouble walking the prime-time ratings tightrope. The live special featuring Nik Wallenda traversing the Grand Canyon on a tightrope with a show called “Skywire Live with Nik Wallenda," the pre-show and the actual show, pulled in a Nielsen average 8.5 million total viewers for the 80-minute show between 9 p.m. and 10:20 p.m. The key “walk” segment pulled in some 13 million viewers between 9:38 p.m. and 10:01 p.m. Wallenda is the first person to walk the Grand Canyon on a tightrope. By way of comparison, the highest-viewed broadcast network show of Sunday night -- a rerun of CBS’ “60 Minutes" -- averaged 8.2 million viewers between 7 p.m. and 8 p.m. CBS averaged 4.9 million viewers for all of Sunday night, tops for all networks. The best-rated 18-49 show was a “Family Guy” rerun at 9 p.m. getting to a 1.5 rating/4 share among 18-49 viewers.“Skywire Live” was followed by “Naked and Afraid," which took in 4.2 million viewers between 10:20 p.m. and 11:20 p.m. p> “Skywire” was Discovery Channel’s highest-rated live event ever -- but not the best-rated Discovery special. The show had a 6.43 household rating and a 4.7 rating among 25-54 viewers. These were the best results since “Walking with Dinosaurs” (a 7.99 household rating and a 6.16 rating among 25- to-54-year-olds) and “Raising the Mammoth” (a 7.84 household rating and 6.40 rating among 25- to-54-year-olds in March/April 2000. Discovery says the event tallied 1.3 million Tweets, the most social show across broadcast and cable in the U.S., per Bluefin Signals, SocialGuide and Trendrr.