A girl rides a donkey as another walks by at the Shawqaba camp for internally displaced people who were forced to leave their villages by the war in Yemen's northwestern province of Hajjah March 12, 2016. In northwest Yemen, one of the poorest countries in the Middle East, about 400 families uprooted by the war have been stuck in the Shawqaba camp in Hajjah province for the past year. Residents live in poorly built huts that protect them neither from summer heat nor winter cold in a camp that lacks the most basic services. (Photo by Abduljabbar Zeyad/Reuters)

A woman dressed up for Halloween travels on a Metro train in São Paulo, Brazil on October 30, 2017. (Photo by Cris Faga/Rex Features/Shutterstock)

People look at a Christmas tree decorated with colourful lights at a residential compound in Beijing on December 8, 2017. (Photo by Nicolas Asfouri/AFP Photo)

A zoo staff feeds crocodiles as visitors look on at the Malabon Zoo in Malabon City, north of Manila, Philippines 21 December 2017. Wearing Santa Claus hats for the upcoming Christmas season, owner Manny Tangco (R, holding megaphone) and some select animals gave visitors a tour of the 28-year-old zoo. (Photo by Rolex Dela Pena/EPA/EFE)

Canadian actress Ellen Page and wife Emma Portner arrive at “The Cured” – Los Angeles Special Screening on February 20, 2018 at AMC Dine-In Sunset 5 in West Hollywood, CA. (Photo by Parisa Michelle/Splash News and Pictures)

Alexo Carmona, 2, looks at Coco, a two-year-old pony, in downtown Havana, in this March 6, 2015 file photo. Nearly a quarter of a million people follow the Reuters Instagram account – and it's still growing fast. To mark the mid-point of 2015, Reuters has compiled the twenty most-liked pictures so far. This picture was 20th most popular. (Photo by Alexandre Meneghini/Reuters)

A women wearing a mask to protect from extreme smog visits the Tiananmen Gate in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. (Photo by Damir Sagolj/Reuters)

Labourers load a three-wheeled vehicle onto the back of a van at the Mercato market in Addis Ababa October 9, 2015. Addis Ababa's “Mercato” – Italian for “market” – is reputedly the biggest open-air market in Africa, lying in the west of the capital. (Photo by Tiksa Negeri/Reuters)