An environmental activist adjusts his mask while taking part in “The Dead Sea Swim Challenge”, swimming from the Jordanian to Israeli shore, to draw attention to the ecological threats facing the Dead Sea, in Kibbutz Ein Gedi, Israel November 15, 2016. Swimmers from around the world plunged into the salty waters of the Dead Sea on Tuesday to attempt a seven-hour swim across the fabled lake in a bid to draw attention to its environmental degradation. Wearing protective masks and snorkels, 25 swimmers paddled through the muddy water to attempt the 9-mile (15-kilometer) swim from Jordan to Israel. (Photo by Nir Elias/Reuters)

An air tanker drops fire retardant on flames as firefighters continue to battle against the Detwiler fire in Mariposa, California on July 19, 2017. The Detwiler fire is currently at 7 percent containment and has burned more than 45,000 acres and destroyed eight structures. (Photo by Josh Edelson/AFP Photo)

A family of children share a bath in Japan, circa 1965. (Photo by Three Lions/Hulton Archive/Getty Images)

Police officers control the crowd (rear) while surrounding a man (front C) suspected to be involved in opening fire on a beachside hotel in Sousse, Tunisia, as a woman reacts (R), June 26, 2015. At least 27 people, including foreign tourists, were killed when at least one gunman opened fire on a Tunisian beachside hotel in the popular resort of Sousse on Friday, an interior ministry spokesman said. Police were still clearing the area around the Imperial Marhaba hotel and the body of one gunman lay at the scene with a Kalashnikov assault rifle after he was shot in an exchange of gunfire, a security source at the scene said. (Photo by Amine Ben Aziza/Reuters)

As the sun rises, Gentoo penguins start their day on Wednesday, February 17, 2016, on Sea Lion Island, Falkland Islands. Sea Lion Island, which lies about 10 miles to the south of mainland East Falkland, is the southern most human-inhabited island of the more than 750 islands and islets of the Falkland Islands. (Photo by Jahi Chikwendiu/The Washington Post)

An American flag is visible in the windows of the cupola aboard the International Space Station. Thanks to a bill passed by Texas legislators in 1997 that put in place technical voting procedure for astronauts – nearly all of whom live in Texas – they have the ability to vote from space through specially designed absentee ballots. To preserve the integrity of the secret vote, the ballot is encrypted and only accessible by the astronaut and the county clerk responsible for casting the ballot. (Photo by NASA)

Ashley Ward kayaks down a flooded street that has been inundated with water from Hurricane Harvey on August 27, 2017 in Houston, Texas. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in areas of Texas over the next couple of days. (Photo by Scott Olson/Getty Images)

A cat dressed in a traditional outfit takes part during the Orthodox Christmas celebration in Kiev, Ukraine on January 7, 2020. Orthodox Christians celebrate Christmas Day on December 25 of the older Julian calendar, which currently corresponds to January 7 in the Gregorian calendar. (Photo by Pavlo Gonchar/SOPA Images/LightRocket via Getty Images)