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)

An India Christian devotee reenacts the sufferings of Jesus Christ on the occasion of Good Friday in Mumbai, India, Friday, March 29, 2013. Christians all over the world are marking Good Friday, the day when Christ was crucified. (Photo by Rajanish Kakade/AP Photo)

A young man weaves palm fronds into the shape of a cross before the start of a Mass to observe Palm Sunday, at the Metropolitan Cathedral, in Managua, Nicaragua, Sunday, March 29, 2015. For Christians, Palm Sunday marks the start of Holy Week ahead of Easter, commemorating Jesus Christ's entrance into Jerusalem, when his followers laid palm branches in his path. (Photo by Esteban Felix/AP Photo)

A woman in traditional Malaysian attire welcomes leaders to the official dinner at the venue of the Association of Southeast Asian Nations (ASEAN) Summit in Kuala Lumpur, Malaysia November 21, 2015. (Photo by Jorge Silva/Reuters)

A participant in the 5th Lady on Bicycle annual festival opens her bag in the back basket of her tricycle in the Sokolniki park in Moscow on August 6, 2017. The festival's aim is to capture the city's fashionable women on vintage style bicycles. (Photo by Mladen Antonov/AFP Photo)

A participant in costume uses a mobile phone at a Halloween event in Kawasaki, south of Tokyo, Japan October 29, 2017. (Photo by Kim Kyung-Hoon/Reuters)

Women jump into the water during a traditional New Year bath in the Adriatic sea in Portoroz, Slovenia on January 1, 2018. (Photo by Jure Makovec/AFP Photo)

Costumed guests arrive for the “Life Ball” charity event at the Rathaus city hall in Vienna, Austria, 10 June 2017. The 24th Life Ball is a charity fundraiser for HIV and Aids projects. (Photo by Christian Bruna/EPA/EFE)