A Shi'ite worshiper bleeds after cutting his scalp in a ritual display of mourning during an Ashura commemoration ceremony outside Kadhimiya shrine on December 6, 2011 in Baghdad, Iraq. Ashura marks the death of Prophet Muhammad's grandson the revered Imam Hussein in Karbala, Iraq in 680 AD. Shi'ite festivals were prohibited during the time of Sunni dictator Saddam Hussein's rule. (Photo by Mario Tama/Getty Images)

Firefighting teams try to extinguish an oil fire November 27, 2016 as smoke billows from one of the remaining oil wells set ablaze by ISIL in their retreat from Qayyarah at the start of the Mosul offensive which began more than a month prior. (Photo by Byron Smith/ZUMA Wire/Rex Features/Shutterstock)

A Iraqi soldier of the 9th division is seen within a Humvee in Shyma district in Mosul, Iraq, Tuesday, December 6, 2016. Iraqi forces, backed by the U.S.-led international coalition, launched a campaign in October to retake Mosul, the country's second largest city and IS's last major urban bastion in Iraq. (Photo by Manu Brabo/AP Photo)

A member of Iraqi rapid response forces fires a rocket launcher during a battle with Islamic State militants in the district of Yarimja in southern Mosul, Iraq, January 18, 2017. (Photo by Alaa Al-Marjani/Reuters)

An Iraqi special forces soldier shot dead an Islamic State suicide bomber in Mosul, Iraq March 3, 2017. (Photo by Goran Tomasevic/Reuters)

Iraqi paramilitary troops fire towards Islamic State militants during a battle with Islamic State militants on the outskirts of the ancient city of Hatra near Mosul,Iraq April 26, 2017. (Photo by Reuters/Stringer)

Ricardo Azevedo rides his Honda NX 200 motorbike, which he converted to be powered by water, in Salto, northwest of Sao Paulo, Brazil, August 6, 2015. The Sao Paulo civil servant built the motorbike, which can cover up to 500 kilometres (311 miles) fuelled by just one litre of water. Dubbed “Moto Power H2O” the bike is powered by the process of electrolysis, which breaks the water molecule down into its constituent elements. (Photo by Nacho Doce/Reuters)

Vultures gather to eat waste in Bica beach, on the banks of the Guanabara Bay, with the Sugar Loaf mountain in background, 500 days ahead the Rio 2016 Olympic Games in Rio de Janeiro March 24, 2015. As part of its Olympic bid, Rio promised to clean up 80 percent of the bay for the games. But local government officials have already admitted that a cleanup by 2016 is not achievable. Despite millions of dollars of investment over the years, the bay still stinks of sewage. Sailors who visited the city for test events complained of a floating sofa and a dead dog in the water. (Photo by Ricardo Moraes/Reuters)