Members of South Korean girl group Gfriend rehearse in Seoul December 23, 2014. Thousands of Korean children dream of becoming household names like rapper Psy, whose 2012 “Gangnam Style” video was a global YouTube hit, often putting up with punishing schedules in the hope of one day making it big in the music industry. A recent survey of pre-teens showed that 21 percent of respondents wanted to be K-pop (Korean pop) stars when they grow up, the most popular career choice. (Photo by Kim Hong-Ji/Reuters)

A handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)

Bella Hadid, Vittoria Ceretti and Gigi Hadid are seen backstage ahead of the Alberta Ferretti show during Milan Fashion Week Spring/Summer 2018 on September 20, 2017 in Milan, Italy. (Photo by WWD/Rex Features/Shutterstock)

Radio City Music Hall Rockettes perform after days of rehearsal and routine polished to perfection at the Radio City Music Hall in New York City on July 26, 1949. (Photo by Ivan Dmitri/Getty Images)

Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

A fireball erupts from a 16-inch gun on the battleship USS Wisconsin during a live fire exercise in the Persian Gulf, October 13, 1990. The ship is in the Gulf as part of Operation Desert Shield. (Photo by John Gaps III/AP Photo)

A retired man (L) looks toward two girls wearing miniskirts, July 13, 1969 in Nice, France. (Photo by AFP Photo)

Multicolored nets are set under olive trees to collect the olives on November 27, 2013 in Castagniers, southeastern France. (Photo by Valery Hache/AFP Photo)