Nuns from the United States dance as they wait for the Holy Mass with Pope Francis (not seen) at the Campus Misericordiae in Brzegi, Poland, 31 July 2016. Today Pope Francis will celebrate the holy mass ending the World Youth Day 2016 in Poland. (Photo by Marcin Obara/EPA)

2016 Rio Olympics, Swimming, Preliminary, Men's 100m Backstroke, Heats, Olympic Aquatics Stadium, Rio de Janeiro, Brazil on August 7 2016. Christopher Reid (RSA) of South Africa competes. (Photo by Dominic Ebenbichler/Reuters)

José Pereira de Souza plays an accordion as actress and model Tatiana Melo gives a television interview in Feira Nordestina outside of the Olympic periphery on Wednesday, August 17, 2016. (Photo by Aaron Ontiveroz/The Denver Post)

A model train travels past a scaled model of New York's Grand Central Station built entirely with plant parts during a media preview of the 25th annual Holiday Train Show at the New York Botanical Garden in the Bronx borough of New York City, U.S., November 14, 2016. (Photo by Mike Segar/Reuters)

A cat walks past a Soyuz space ship installed at a museum, at the Russian leased Baikonur cosmodrome, Kazakhstan, Tuesday, November 15, 2016. The start of the new Soyuz mission to the International Space Station (ISS) is scheduled on early Friday, Nov. 18 local time. The Russian rocket will carry French astronaut Thomas Pesquet, Russian cosmonaut Oleg Novitsky and U.S. astronaut Peggy Annette Whitson. (Photo by Dmitri Lovetsky/AP Photo)

A woman takes a selfie in front of a sculpture of a rooster that local media say bears resemblance to U.S. President-elect Donald Trump, outside a shopping mall in Taiyuan, Shanxi province, China December 30, 2016. (Photo by Jon Woo/Reuters)

In this January 24, 2017 photo, boxer Idamerys Moreno wraps a bandage on her hand before a training session at a sports center in Havana, Cuba. Boxing has long been an athletic engine for Cuba, which has won 72 Olympic medals in that category but women are not allowed to box. (Photo by Ramon Espinosa/AP Photo)

Female soldiers march in formation in St Petersburg' s Palace Square during a rehearsal of a Victory Day military parade marking the 72 nd anniversary of the victory over Nazi Germany in the 1941-1945 Great Patriotic War, the Eastern Front of World War II, on May 5, 2017. (Photo by Peter Kovalev/TASS)