Attendees at Wizard World Comic Con walk through hallways in Chicago, Illinois, United States, August 22, 2015. (Photo by Jim Young/Reuters)

The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

Iraqi forces gather during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016. (Photo by Reuters/Stringer)

Girls sits on a bench during summer at the Central Park in New York, United States, 2011. (Photo by An Rong Xu)

Gloria Grahame in state of undress in a scene from the film “Naked Alibi”, 1954. (Photo by Universal/Getty Images)

In this Wednesday, May 23, 2012 photograph, a young deer and a cat share a moment in Feench village near Jodhpur, Rajasthan state, India. (Photo by AP Photo)

Commuters ride on the roof of a Jakarta state rail train at Cawang train station on January 27, 2012 in Jakarta, Indonesia. (Photo by Ulet Ifansasti/Getty Images)

A woman poses for a photograph during Holi celebrations in the town of Barsana in the state of Uttar Pradesh, India, March 6, 2017. (Photo by Cathal McNaughton/Reuters)