Sheep walk as they are herded to summer pastures in Serra da Estrela, near Seia, Portugal June 27, 2015. In late June, shepherds young and old in the Seia region of central Portugal start guiding sheep, goats and cattle to the Serra da Estrela, the country’s highest mountains, in search of better pastures. There they stay until the end of September. Modern-day shepherds may have mobile phones to keep in touch with family and friends, but their lifestyle has changed little for centuries. The sound of cowbells and the bark of longhaired mastiffs starts early in the morning as the animals – often decorated with traditional woollen balls on their horns – are herded up steep, narrow paths. (Photo by Rafael Marchante/Reuters)

Ice swimmer Klaudia prepares to swim in a filled up water kettle in an ice cave inside the Nature Ice Palace, with a hight of 3,250 meters (10,663 feet) above sea level, at Hintertux Glacier near Hintertux, some 480 kilometers (298 miles) western of Vienna, Austria, 28 July 2018. (Photo by Christian Bruna/EPA/EFE)

Russian President Vladimir Putin aims a sniper rifle during a visit to the Patriot military exhibition center outside Moscow, Russia, Wednesday, September 19, 2018. Putin chaired a meeting that focused on new arms programs. (Photo by Alexei Nikolsky/Sputnik/Kremlin Pool Photo via AP Photo)

A view of Worker and Kolkhoz Woman, a sculpture by Vera Mukhina, at the main entrance to Moscow's VDNKh exhibition center in Moscow, Russia on September 27, 2017. (Photo by Dmitry Serebryakov/TASS/Barcroft Images)

Picture dated October 23rd, 2018 shows brother and sister Henry (7) and Lily Sales (9) getting in some early practice for the World Puddle Jumping Championships at Wicksteed Park in Kettering, Northants, UK. Organisers have made more puddles than ever before in an attempt to make this year's competition the biggest and best yet. They are also hoping competitors will set a new record for the most people jumping in puddles at the same time. Judges will give scores based on the height of the jump, enthusiasm, distance of splash and stickability (the amount of mud which clings to each competitor). (Photo by Geoff Robinson Photography)

Alessandra Ambrosio shows off some cleavage during a photoshoot in Miami, Florida on January 23, 2019. She wore a leather jacket and skirt and some over sized sunglasses as she flicked her hair in the Little Havana district of Miami for Italian Elle magazine. (Photo by Splash News and Pictures)

Self-employed pedicab driver Danilo Guerra, 25, uses his mobile phone as he waits for clients in downtown Havana April 12, 2016. (Photo by Alexandre Meneghini/Reuters)

Katy Perry poses backstage during rehearsals for the 2017 MTV Video Music Awards at The Forum on August 25, 2017 in Inglewood, California. (Photo by John Shearer/Getty Images for MTV)