A woman laughs as she takes part in the “Domingo Fareleiro” (Floury Sunday in Galician) festival in the village of Xinzo de Limia, northwestern Spain, on January 21, 2018. Domingo Fareleiro (Floury Sunday) takes place annually in Xinzo de Limia, Spain, in a unique celebration that gives the starting signal for a long festive period known as Entroido, or Carnival. (Photo by Miguel Riopa/AFP Photo)

A tourist stands in front of Italy's Mount Etna as it spews lava during an eruption on the southern island of Sicily, Italy on March 1, 2017. (Photo by Antonio Parrinello/Reuters)

In this March 22, 1975 file photo, a refugee clutches a baby as a government helicopter gunship carries them away near Tuy Hoa, Vietnam, 235 miles northeast of Saigon. They were among thousands fleeing from Communist advances. AP Photographer Nick Ut will be retiring from the AP in March 2017 after 51 years of taking photographs from the front lines of the Vietnam War to the red carpets of Hollywood. (Photo by Nick Ut/AP Photo)

Handler Jorge Garcia-Bengochea holds Honor, a miniature therapy horse from Gentle Carousel Miniature Therapy Horses, as they visit with patients at the Kravis Children's Hospital at Mount Sinai in the Manhattan borough of New York City, March 16, 2016. Some of the most powerful medicine delivered to young patients at Mount Sinai Hospital in New York on Wednesday came in a package less than 32 inches tall and with a tail. Honor, a 10-month-old colt with Gentle Carousel Miniature Therapy Horses, trotted into the hearts of dozens of children and teens being treated at the Manhattan hospital. (Photo by Mike Segar/Reuters)

A young monk takes his food from the dining hall at Changangkha Lhakhang temple in Thimphu, Bhutan, April 13, 2016. (Photo by Cathal McNaughton/Reuters)

Andrew Hepher, Vice President of Lubricants Technology, Shell unveils the Shell Concept Car in Beijing, China, Friday, April 22, 2016. Built as proof of energy efficiency that can be achieved with the latest technologies, Shell unveiled the concept car ahead of the bi-annual Beijing Auto Show where the world's top car manufacturers will showcase their own upcoming products. (Photo by Ng Han Guan/AP Photo)

An employee walks near a rotary dredge which works on the coal face of the Borodinsky opencast colliery, near the Siberian town of Borodino, east of Krasnoyarsk, December 9, 2014. The Borodinsky colliery, 9 km (5.6 miles) long and more than 100 meters (328 feet) deep, annually produces more than 20 million tons of coal and is considered to be the biggest opencast coal mine in Russia, according to official representatives. (Photo by Ilya Naymushin/Reuters)

A member of a comparsa, a Uruguayan carnival group, dances during the Llamadas parade in Montevideo February 5, 2015. Thousands of people crowd the capital's Barrio Sur as costumed drummers and dancers kick off the street fiesta known as Llamadas which has traditional Afro-Uruguayan roots. The fiesta, also known in Spanish as “The Calls”, started during the colonial period as a slave parade on the city streets. (Photo by Andres Stapff/Reuters)