Medics carry a wounded person at the scene after an attack at a popular nightclub in Istanbul, early Sunday, January 1, 2017. Istanbul Governor Vasip Sahin said that an armed assailant has opened fire at a nightclub in Istanbul during New Year's celebrations. Turkish authorities have banned distribution of images relating to the Istanbul attack within Turkey. (Photo by IHA via AP Photo)

Passengers prepare to take part in the No Pants Subway Ride in Prague, Czech Republic, Sunday, January 8, 2017. The No Pants Subway Ride began in 2002 in New York as a stunt and has taken place in cities around the world since then. (Photo by Petr David Josek/AP Photo)

A balloon dips into Bald Eagle lake during the 36th Annual Hot Air Balloon Rodeo in Steamboat Springs, Colorado on July 9, 2017. (Photo by Jason Connolly/AFP Photo)

Revelers march during the Greenwich Village Halloween Parade, Tuesday, October 31, 2017, in New York. (Photo by Andres Kudacki/AP Photo)

Take me away, deer, Russia. The Nenet people of Arctic Russia use reindeer and sledges as a prime mode of transport. The animals’ navigational ability means that in severe conditions they are sometimes the only hope of survival. (Photo by Kamil Nureev/Smithsonian Photo Contest)

An Iraqi girl walks past a donkey-drawn cart carrying bricks at a brick factory near the central Iraqi shrine city of Najaf on May 16, 2017. (Photo by Haidar Hamdani/AFP Photo)

Planned improvements to Rio’s favelas have meant increases in rent, forcing the poorest families into squatting in unoccupied buildings. Photographer Tariq Zaidi visits the Mangueira community favela, less than 1km from the showpiece Maracanã stadium, to see what life is like for the women living there. Here: Victoria, 12, at her home in Mangueira. (Photo by Tariq Zaidi/The Guardian)

A purebred Spanish horse is pictured during the Sicab International Pre Horse Fair which is dedicated in full and exclusively to the purebred Spanish horse in the Andalusian capital of Seville, southern Spain November 17, 2015. (Photo by Marcelo del Pozo/Reuters)