Hospitality staff members laugh as they stand on Tiananmen Square before the closing ceremony of China's 19th Party Congress at the Great Hall of the People in Beijing, Tuesday, October 24, 2017. The ruling Communist Party on Tuesday formally lifted Xi Jinping's status to China's most powerful ruler in decades, setting the stage for the authoritarian leader to tighten his grip over the country while pursuing an increasingly muscular foreign policy and military expansion. (Photo by Mark Schiefelbein/AP Photo)

Lava cascades down the slopes of Mayon volcano as seen from Legazpi city, Albay province, around 340 kilometers (210 miles) southeast of Manila, Philippines, Monday, January 15, 2018. More than 9,000 people have evacuated the area around the Philippines' most active volcano as lava flowed down its crater Monday in a gentle eruption that scientists warned could turn explosive. (Photo by Earl Recamunda/AP Photo)

The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

Pablo Picasso, famed 66-year-old Spanish artist who has lived most of his life in France, suns himself on a boat on the beach at Golfe Juan in Vallauris on the French Riviera on March 10, 1948. Entering a new period in his varied artistic career, Picasso has turned to painting pottery at the nearby town of Vallauris. (Photo by AP Photo)

In a photo taken on July 29, 2018 instructor Kim Ju Yang (20) holds a North Korean- made assault rifle as she poses for a portrait at the Meari shooting range in Pyongyang. The Meari shooting range offers customers the opportunity to shoot a number of North Korean and foreign- made firearms, most of which have been modifed to fire .22 calibre ammunition costing one US dollar per round. (Photo by Ed Jones/AFP Photo)

Strokkur geyser against cloudy sky at sunset. Strokkur is a fountain geyser located in a geothermal area beside the Hvítá River in Iceland in the southwest part of the country, east of Reykjavík. It is one of Iceland's most famous geysers, erupting once every 6–10 minutes. Its usual height is 15–20 m, although it can sometimes erupt up to 40 m high. (Photo by Teatsche Dijkhuis/Getty Images/EyeEm)

A participant dressed in a traditional devil costume walks from house to house during the traditional St. Nicholas parade on December 3, 2016 in village of Francova Lhota, Czech Republic. This type of parade is one of the most popular age-old traditions in a few villages in the Wallachia region of Eastern Czech Republic. St. Nicholas and company roam the streets going from house to house, for two or three days as St. Nicholas gives sweets and tiny gifts as a present to children and the devils get up to mischief. (Photo by Matej Divizna/Getty Images)

Robert Galvan, who is on death row for murder, speaks to members of the media at the Adjustment Center yard during a media tour of California's Death Row at San Quentin State Prison in San Quentin, California December 29, 2015. America's most populous state, which has not carried out an execution in a decade, begins 2016 at a pivotal juncture, as legal developments hasten the march toward resuming executions, while opponents seek to end the death penalty at the ballot box. (Photo by Stephen Lam/Reuters)