Popular Mobilization Forces (PMF) fires towards Islamic State militants during a battle with Islamic State militants, west of Mosul, Iraq February 22, 2017. (Photo by Reuters/Stringer)

People dressed as zombies take part in a “Zombie Walk” parade in Athens, Greece, February 25, 2017. (Photo by Michalis Karagiannis/Reuters)

A picture taken on March 16, 2017 shows women dressed up as mermaids posing by a pool at a mermaid training school in Moscow. Russian women who have dreamt of becoming a mermaid since their youngest years, start turning their fantasies into reality with a new type of fitness – mermaid swimming. (Photo by Natalia Kolesnikova/AFP Photo)

Mermaid Hales Parcells geets children as she performs at the Virginia Aquarium in Virginia Beach, Va., Monday, April 3, 2017. The Aquarium presents a mermaid show one night each week during the month of April. (Photo by Steve Helber/AP Photo)

Italian Air Force's aerobatic demonstration team, the Frecce Tricolori leave colourful vapour trails as they fly over the Altare della Patria monument on Republic Day (Festa della Repubblica) in Rome, Italy, 02 Jun 2017. The anniversary marks the founding of the Italian Republic in 1946. (Photo by Massimo Percossi/EPA)

Summer Zhai and Vicky He, dressed as characters from the anime "Love Live!", rest on stairs during day two of New York Comic Con in Manhattan, New York, October 9, 2015. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields at the Jacob Javitz Convention Center on Manhattan's West side. (Photo by Andrew Kelly/Reuters)

Angele Blank, right, and Virginia Promeyrat wait for the start of the Greenwich Village Halloween Parade, Saturday October 31, 2015, in New York. (Photo by Tina Fineberg/AP Photo)

Nuns react at the arrival of Pope Francis at the St. Mary's school to attend a meeting of clergy and religious in Nairobi, Kenya, 26 November 2015. Pope Francis is on a six days visit that will take him to Kenya, Uganda and the Repulic of Central Africa from 25 to 30 November. (Photo by Daniel Dal Zennaro/EPA)