American free climber Dean Potter walks on a 41-meter-long and two-centimeter-wide slackline over Enshi Grand Canyon at an altitude of 1,800m on April 22, 2012 in Enshi, Hubei Province of China. Potter successfully finished the lone slackline walk in about three minutes without taking any protective measures. (Photo by ChinaFotoPress/ChinaFotoPress)

In this April 28, 2015 file photo, heads of tuna on a cart are carried by a fish dealer after the day's auction at Tsukiji Wholesale Market in Tokyo. In one of the biggest of Japan's many New Year holiday rituals, early on Tuesday, January 5, 2016, Tokyo's Tsukiji market will auction off with much fanfare a huge, glistening tuna, likely destined for one of the big sushi chains. If all goes as planned, it will be the last such auction at 80-year-old Tsukiji. (Photo by Shuji Kajiyama/AP Photo)

Visitors walk past vintage and classic cars displayed by Bonhams auction house, during an exhibition, at the Grand Palais in Paris, Wednesday, February 4, 2015. The Grand Palais is staging an exhibition of vintage cars, to be followed by a sale of historic cars by Bonhams auction house on Thursday. (Photo by Jacques Brinon/AP Photo)

Figure Skating, ISU Grand Prix of Figure Skating NHK Trophy 2016/2017, Ice Dance Short Dance, Sapporo, Japan on November 26, 2016. Kaitlin Hawayek and Jean-Luc Baker of the U.S. compete. (Photo by Issei Kato/Reuters)

Apollinariia Panfilova and Dmitry Rylov of Russia perform in the Pairs Short Program during day one of the ISU Grand Prix of Figure Skating Rostelecom Cup at Megasport Arena on November 20, 2020 in Moscow, Russia. (Photo by Evgenia Novozhenina/Reuters)

The space shuttle Endeavour is transported to the California Science Center in Exposition Park from Los Angeles International Airport (LAX) in Los Angeles, California. (Photo by Kevork Djansezian)

Tarah Kayne and Daniel O'Shea of the U.S. perform during the Pairs short program at the Skate America figure skating competition in Milwaukee, Wisconsin October 23, 2015. Fifty-six Olympic and world championship athletes are competing in the event, which is the first of six stops on the International Skating Union (ISU) Grand Prix of Figure Skating Series. (Photo by Lucy Nicholson/Reuters)