An Iraqi soldier stands guard as a pipeline burns in the background after an explosion 30 kilometers (20 miles) northeast of Tikrit, Iraq, Monday, February 11, 2008. (Photo by Bassem Daham/AP Photo)

Indian women wearing traditional attire take a “selfie” with an Indian man dressed as King 'Mahabali' during the Hindu harvesting festival Onam celebrations in Bangalore, India, 28 August 2015. Local people put flower mats in front of their houses, to welcome the King Mahabali, a past ruler of Kerala southern India, during the ten-day festival. (Photo by Jagadeesh N. V./EPA)

In this May 4, 2014 photo, a miner holds an amalgam of mercury and gold he mined after working a 28-hour shift at an illegal gold mining process, in La Pampa, in Peru's Madre de Dios region. Thousands of artisanal gold miners sweat through the long shifts and endure, for a few grams of gold, the perils of collapsing earth, limb-crushing machinery and the toxic mercury used to bind gold flecks. (Photo by Rodrigo Abd/AP Photo)

South Korea's Black Eagles aerobatics team performs an aerial display forming a Ying and Yang logo during the Singapore Airshow at Changi exhibition center in Singapore on February 16, 2016. (Photo by Roslan Rahman/AFP Photo)

A truck driver naps under his truck at the fancy bazaar area during the twelve hours Assam bandh or strike in Guwahati, Assam, India, 23 October 2018. At least 46 organisations are observing a 12-hour bandh across the state to protest against the Centre's bid to clear the Citizenship (Amendment) Bill 2016, in the Winter Session of Parliament. (Photo by EPA/EFE/Stringer)

Yogis, Israeli and foreigners, participate in the Arava Yoga Annual festival at the ancient copper mines area of the Timna Valley, in the southern Arava region of Israel, north of Eilat on November 2, 2018. (Photo by Menahem Kahana/AFP Photo)

University students demonstrate against the crisis in the public education, budget cuts and a tax reform project announced by the government of Ivan Duque in Medellin, Colombia on December 13, 2018. (Photo by Joaquín Sarmiento/AFP Photo)

The northern lights, or aurora borealis, appear in the sky over the Bamburgh lighthouse at Stag Rock in Northumberland, England on September 28, 2016. (Photo by Owen Humphreys/PA Wire via ZUMA Press)