A woman cleans her boat after a snowfall in Srinagar, December 13, 2019. (Photo by Danish Ismail/Reuters)

A mahout cleans the dust from his elephant in Ahmedabad, India, February 8, 2017. (Photo by Amit Dave/Reuters)

An Armatix employee holds a “smart gun” by the company at the Armatix headquarters in Munich May 14, 2014. The gun is implanted with an electronic chip that allows it to be fired only if the shooter is wearing a watch that communicates with it through a radio signal. If the gun is moved more than 10 inches (25 cm) from the watch, it will not fire. A Maryland gun shop owner has dropped his plan to be the first in the United States to sell the so-called “smart gun” after a backlash that included death threats. (Photo by Michael Dalder/Reuters)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

A Hawaiian cleaner wrasse provides its cleaning services to a yellowfin goatfish in a reef community off the Big Island in Hawaii. Cleaner species help rid their hosts of ectoparasites, dead tissue, bacteria and fungi. Studies have shown cleaning to play a vital role in keeping many reef ecosystems healthy. (Photo by Marty Snyderman/Caters News Agency)

Female sea lion “Sarasa” holds a hose with her mouse to help a trainer clean her room at the Shinagawa Aqua Stadium aquarium in Tokyo on December 30, 2014. The aquarium is carrying out year-end general cleaning of their facilities. (Photo by Yoshikazu Tsuno/AFP Photo)

Three young women preparing a guy. They are sitting him on a keg labelled “gun powder”. (Photo by Fox Photos/Getty Images). 1929

Turkana tribesmen walk with guns to protect their cattle from rival tribes near Baragoy, Kenya August 4, 2017. (Photo by Goran Tomasevic/Reuters)