NASA astronaut Reid Wiseman and European Space Agency astronaut Alexander Gerst (not shown) works outside the space station's Quest airlock in the first of three spacewalks for the Expedition 41 crew aboard the International Space Station in this NASA image released October 8, 2014. (Photo by Reuters/NASA)

A woman wearing a traditional "mantilla" dress takes part in an open-air mass to celebrate Madrid's patron saint La Almudena Virgin in Madrid, Spain, November 9, 2015. (Photo by Susana Vera/Reuters)

Vigilantes armed with automatic rifles patrol the streets of Bujumbura, a city plagued by killings and violence as Burundi's crisis deepens. Here: an armed vigilante holds an AK-47 rifle in the center Bujumbura, Burundi, November 20, 2015. (Photo by Goran Tomasevic/Reuters)

Nuns react at the arrival of Pope Francis at the St. Mary's school to attend a meeting of clergy and religious in Nairobi, Kenya, 26 November 2015. Pope Francis is on a six days visit that will take him to Kenya, Uganda and the Repulic of Central Africa from 25 to 30 November. (Photo by Daniel Dal Zennaro/EPA)

Men dressed as “Krampuss” prepare to parade at Munich's Christmas market, December 13, 2015. Young single men will wear the traditional attires known as “Krampusse”, consisting of animal skins and masks, with large cow-bells to make loud and frightening noises and parade through the city. They follow “Saint Nicholas” from house to house in December each year to bring luck to the good and punish the idle. (Photo by Michael Dalder/Reuters)

Miners search for jade stones at a mine dump at a Hpakant jade mine in Kachin state, Myanmar November 25, 2015. Using heavy earth-excavators and explosives, miners have been tearing into Myanmar's northern hills in recent months, in a rush to excavate more jade from the world's richest deposits of the gemstone before a new government takes office next year. (Photo by Soe Zeya Tun/Reuters)

The Kremlin's Spasskaya (Saviour) Tower, covered by scaffolding, is seen behind the mausoleum of Soviet state founder Vladimir Lenin at the Red Square in Moscow, December 23, 2014. The restoration works will last until the spring of 2015, according to local media. (Photo by Sergei Karpukhin/Reuters)

Frog legs it! Indonesian flying frog tries to hitch a ride on snail's back before realising it would be quicker to hop it alone. A tiny frog struck up an unlikely friendship with a giant African land snail after clambering onto its shell to catch a ride. (Photo by Hendy Mp/SOLENT/Visual Press Agency)