Employees of the Park Royal resort wait for a shuttle to take them to work early in the morning on April 2, 2015 in Acapulco, Mexico. Despite problems with cartel violence Semana Santa is one of the biggest tourist weeks of the year in Acapulco, a city whose entire economy depends on tourism, and officials expect around 350,000 mostly Mexican visitors this week. (Photo by Jonathan Levinson/The Washington Post)

North Korean leader Kim Jong Un (front) stands on the conning tower of a submarine during his inspection of the Korean People's Army (KPA) Naval Unit 167 in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang June 16, 2014. (Photo by Reuters/KCNA)

Dr. P.A. Smithe was sent by the American Red Cross as a doctor and surgeon to work at a hospital in Vienna. He sailed to Europe in December 1915 and returned home in August 1916, according to his daughter, who donated his images to the National World War I Museum. Photo: Turkish army, including cavalry, infantry and artillery. (Photo by Dr. P.A. Smithe/National World War I Museum, Kansas City, Mo.)

A fireman from the London Fire Brigade, wearing a smoke helmet. (Photo by Topical Press Agency/Getty Images). Circa 1908

A workman takes a siesta on a girder during the building of Radio City, the city of New York spread out below. (Photo by General Photographic Agency/Getty Images). Circa 1933

Canberra resident Bruce Gibbons is seen surrounded by grazing kangaroos as he plays a shot during a session on a practice fairway at Gold Creek Golf Club in Canberra, Australia, May 16, 2017. (Photo by Lukas Coch/Reuters/AAP)

An Omani woman prepares for a traditional dance during a ceremony attended by Britain's Prince Charles and his wife, Camilla, Duchess of Cornwall in Muscat, Oman, Saturday, November 5, 2016. The royal couple have started a three-nation royal tour of the Gulf in Oman. (Photo by Kamran Jebreili/AP Photo)

A faithful prays during the Divine Liturgy by Pope Francis at the apostolic Cathedral in Etchmiadzin, Armenia, June 26, 2016. (Photo by David Mdzinarishvili/Reuters)