Shepherds lead their sheep through the centre of Madrid, Spain, Sunday, October 25, 2015. Shepherds have guided a flock of 2,000 sheep through Madrid streets in defense of ancient grazing, droving and migration rights increasingly threatened by urban sprawl and modern agricultural practices. Tourists and city-dwellers were surprised to see the capital's traffic cut to permit the ovine parade to bleat bells clanking its way past the city's most emblematic locations. (Photo by Daniel Ochoa de Olza/AP Photo)

Estonia's olympic team female marathon runners triplets (L-R) Lily, Liina and Leila Luik run during a training session in Tartu, Estonia, May 26, 2016. Leila, Liina and Lily Luik will make Olympics history as the first identical triplets to compete against each other when they cross the start line for the women's marathon in Rio. (Photo by Ints Kalnins/Reuters)

Mamoni Mandal, member of the Rapid Action Force (RAF), attends a training session at a police training school in Kolkata April 15, 2007. (Photo by Parth Sanyal/Reuters)

Participants prepare backstage during Belarus bodybuilding and fitness championship in Minsk April 25, 2015. (Photo by Vasily Fedosenko/Reuters)

Dancers wearing new bikinis perform in front of passers-by and a line of photographers during a promotional flash mob event on a square outside Shinjuku station in Tokyo on July 18, 2016. The event was organized by the Japan Swimsuit Association to promote new swimwear. (Photo by Toru Yamanaka/AFP Photo)

A Naga sadhu, or naked Hindu holy man, performs a ritual inside his tent during Kumbh Mela, or Pitcher festival, at Trimbakeshwar, India, Friday, August 28, 2015. Hindus believe taking a dip in the waters of a holy river during the festival will cleanse them of their sins. The festival is held four times every 12 years. (Photo by Rajanish Kakade/AP Photo)

An H-2A rocket carrying Japan's fourth and final quasi-zenith satellite, the Michibiki No. 4, lifts off from the Tanegashima Space Center in Kagoshima Prefecture, southwestern Japan in this photo taken by Kyodo on October 10, 2017. (Photo by Reuters/Kyodo News)

Enthusiasts gathered at Cad East in Snowdonia National Park, England to take pictures of F-15 Eagle fighters as they completed the Mach Loop, November 2017. (Photo by Caters News Agency)