A child looks at window cleaners work while dressed in sheep (C) and monkey costumes, denoting animal signs of the Chinese zodiac calendar, during an event marking the upcoming end of the year at a hotel in Tokyo, Japan, December 21, 2015. According to the zodiac calendar, 2015 is the year of the sheep and 2016 is the year of the monkey. (Photo by Thomas Peter/Reuters)

Izzy Paskowitz helps Nixee Grace Chanowsky, 4, catch a wave Monday, August 18, 2014 at Wrightsville Beach, N.C. during the Annual Surfers Healing event for children with autism. Hundreds of people made their way to the beach to watch and cheer on the camp that was founded by Israel and Danielle Paskowitz. (Photo by Mike Spencer/AP Photo/The Star-News)

Students pose for a pictures taken by their friends during spring break on the beach in the resort city of Cancun, Mexico, February 27, 2009. (Photo by Israel Leal/AP Photo)

Visitors look on as a man (front) inserts two live snakes through his nose and mouth during a performance at an amusement park to celebrate the 65th anniversary of the founding of the People's Republic of China and the 7-day national day holiday, in Jinhua, Zhejiang province October 1, 2014. (Photo by Reuters/Stringer)

Rihanna holds the pregnant belly of Spc. Ariel Evans during an event promoting her Rogue Man cologne at Ft. Belvoir Exchange on Wednesday, November 12, 2014 in Ft. Belvoir, Va. (Photo by Kevin Wolf/AP Photo)

A soldier poses with a Hythe Mk III Gun Camera during training activities at Ellington Field, Houston, Texas in April of 1918. The Mk III, built to match the size, handling, and weight of a Lewis Gun, was used to train aerial gunners, recording a photograph when the trigger was pulled, for later review, when an instructor could coach trainees on better aiming strategies. (Photo by Harry Kidd/WWI Army Signal Corps Photograph Collection via The Atlantic)

A volcanic eruption at Mount Etna’s Vorgaine crater in Sicily, Italy on December 3, 2015. (Photo by Marco Restivo/Barcroft Media)

Dinosaur robots acting as receptionist greet a hotel employee demonstrating how to check-in to the hotel during a press preview for the newly-opening Henn na Hotel Maihama Tokyo Bay in Urayasu, east of Tokyo, Japan March 15, 2017. The reception desk is handled by robots that speak Japanese, English, Chinese and Korean, as well as porter robots that help guests carry luggage to their rooms. Tasks such as window-cleaning and vacuuming are also handled by robots. Japan's second robot-run hotel Henn na Hotel (“strange hotel” in Japanese) opened on March 15, 2017 as the robot-staffed hotel near Tokyo, operating company H.I.S. Co. said. (Photo by Issei Kato/Reuters)